


Sea Spider

by Bean_reads_fanfic



Category: Iron Man (Movies), Spider-Man - All Media Types, Spider-Man: Homecoming (2017), The Avengers (Marvel Movies)
Genre: Alternate Universe, AoU didn't happen and neither did Civil War, FRIDAY is still Tony's AI because i said so, Gen, Hurt Peter Parker, Irondad, Mer!Peter, Merperson Peter Parker, Precious Peter Parker, Tony Stark Has A Heart, and by 'you' i mean the 6 people who will read this, the most AU AU you will ever read
Language: English
Status: In-Progress
Published: 2019-03-13
Updated: 2019-06-22
Packaged: 2019-11-17 13:07:59
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 22,242
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18099119
Author URL: https://archiveofourown.org/users/Bean_reads_fanfic/pseuds/Bean_reads_fanfic
Summary: “Tell me I’m not the only one seeing this,” Tony prompts, gesturing to their catch.It’s a kid. A teenager, by the looks of him, no more than 15 or 16, with curling brown hair plastered over his forehead and eyes. He lays there prone on his side, covered in cuts- some shallow, some deep, all of them most likely caused by the barbs on the fishnet. Tony can just make out blood matted on the back of his head- he probably hit it on the side of the boat and got himself knocked out. Clinging to his torso is a soaked, faded t-shirt and below that…...below that, his lower body is a tail. A full-on fish tail.(Mer!Peter AU) (IronDad Big Bang 2019)





	1. a twist in the tail

**Author's Note:**

  * For [tumblr user flicker-parker](https://archiveofourown.org/gifts?recipient=tumblr+user+flicker-parker).



> this work is dedicated to my bud @flicker-parker on tumblr, whose input helped build this story 💙

...

...

...

Gray walls. Cold air. Empty hallways.

(This is what he has left.)

 

The boy’s glasses slip down his nose as he huddles in on himself. He’s burrowed in his Uncle’s oversized Mets hoodie, the one he’d given Peter as a gift for his thirteenth birthday just a few weeks before. The boy borrowed it often enough to call it his own before that point, but the formality of unwrapping it along with the other gifts was something that caused Peter to blush and his guardians to laugh. It’s not like he didn’t have things of his own to wear; he just loved the garment because the worn fabric and familiar smell reminded him of the man he loved.

He hugs himself around the middle and lets his shaking fingers grasp at threadbare sleeves, desperate for the hoodie’s comforting abilities to take him away from this nightmare.

“Peter,” someone says softly, pityingly. He looks up.

An adult he vaguely recognizes is standing there. She looks tired-- understandable, since it’s almost 5am-- but still she smiles wanly. She’s dressed nicely, like Aunt May when she goes (went) to work meetings. He can’t remember her name but he thinks she’s a social worker. She’d been there when he woke up here earlier-- when he found out he was the only survivor of the car crash that orphaned the orphan. That was hours ago.

This day seems to be years long at this point.

“I’m so sorry for the wait, honey,” she tells him, kneeling to his level. Her eyes are sad. “Are you ready to go?”

He stares at her uncomprehendingly, saying nothing. In his head he imagines Ben chastising him for being rude to someone so nice, but the thought only makes him bite down on his lip and avert his gaze to the tiled floor. He nods once, a lifeless gesture. A tear slides down his face.

The woman waits for him to get to his feet before wrapping an arm around his thin shoulders and steering him toward the elevator, down several long halls and out into the hospital parking lot. He feels disconnected, like he’s walking in a dream.

 _Please_ , he begs, his lip trembling. _Please let it be a dream_.

“Oh, shoot,” the woman mutters, rummaging through her purse and pockets. “I think I left my phone back inside. Wait right here, okay, Peter? I’ll be one minute.” She indicates the concrete benches nearby, then hurries back through the glass doors.

Peter watches her go impassively. A breeze toys at his bangs and he blinks a bit, the fresh air waking him up from the stupor he’s been locked in for hours.

The sky is still fairly dark, but an orange glow is hinting on the horizon. He can hear birds beginning to chirp, to sing praises to a new day, as if they don’t know that the world has ended.

It’s in that moment that it hits him.

 

He’s alone.

 

The woman will come back and take him to some foster home and he’ll never see his apartment, his home, ( _his family,_ ) ever again.

A sob like a dying heart claws out of his chest and then, almost without conscious decision, his feet start running. He’s small and asthmatic and weak, but he doesn’t care; he runs and runs and runs and welcomes the feeling of burning lungs and aching legs because they drown out a much worse pain threatening to swallow him whole.

He doesn’t pay attention to street signs, has no destination in mind; he just goes where the road takes him. In the blur around him, New York is coming to life with sounds of cars and people going to work and school and whatever else they do in normal days because they don’t know. They don’t know.

He just keeps on, away and away and away from the building wherein lies the two moldering bodies that used to be his aunt and uncle, the only two people left in the world who loved him.

By the time he stops, it’s because he trips on one of his shoelaces that’s come loose. He doesn’t get up, just lays there sprawled awkwardly on the sidewalk, cheek pressed on the asphalt, and pants for several minutes. Eventually he pushes upright, his heart still racing, and looks around. He doesn’t recognize the area he’s in now, but it’s a deserted and bare stretch of road. He guesses by the salt in the air and the distant sound of waves that he’s near the coast.

When he shakily gets to his feet again, he brushes his scraped hands against his knees and keeps moving, albeit at a walking pace this time.

Soon he finds himself on the edge of a highway overlooking the sea. The sun has risen into a bright blue sky, warming some of the morning chill out of the air and sparkling off the water below. He stops and looks out over the horizon and lets tears stream down his face anew. They drop off his chin, fall the 100 feet drop and are lost in the salt water below.

“I don’t know what to do,” Peter cries.

The crest and spray of waves is his only answer.

He’s not at all paying attention to his surroundings, and that’s why when a truck comes hurtling around the bend in the road, he doesn’t know until the driver lays on their horn to urge him out of the way. In his surprise, he stumbles closer to the ledge and loses his balance.

And then he’s falling.

His glasses are lost on the way down, and the rush of air steals his breath and chills his bones. When he hits the water, it’s feet-first and the impact snaps both legs. He couldn’t swim if he wanted to. The ocean envelops him and his lungs scream for air.

He’ll die here and nobody will know. Nobody will care.

 

(He’s _alone_.)

 

Then, out of nowhere, he feels gashes open up in the sides of his neck and suddenly he can breathe again. The pain in his legs goes numb. He can’t feel his lower body.

He blacks out.

 

When he wakes up, everything is different.

 

…

_2 years later_

…

  

“Hey, hey, Nat. Nat, why did the fish cross the road?”

The redhead doesn’t look up. She stays focused on the console as if she hasn’t even heard.

Her lack of interest doesn’t deter the billionaire. “To get to the other _tide,_ ” he says loudly.

Groans fill the air and Tony glances around the boat, looking extremely pleased with himself.

“If you don’t shut up, man, I swear I will kill you… As soon as I’m done throwing up,” Clint whines from where he leans against the rail, his head pillowed in folded arms. His face is slightly green.

“Do you want some ginger chews?” Bruce asks, approaching and holding up a plastic bag to the seasick man. “They’re good for nausea.”

Wordlessly Clint nods in thanks and takes one of the offered candies, stuffing it in his mouth and going back to cursing the moment he left solid ground.

“I thought you super spies would have stronger stomachs,” Tony remarks, joining the other men at the rail. “It’s like you’ve never been on a boat before. It’s too bad too… you’re incapacitated with no choice but to listen to me talk.”

Clint mumbles an unintelligible response into his arms that most likely contains a threat to turn off his hearing aids.

“Okay, okay, I’ll stop,” Tony smirks. “But, hey, have any of you guys heard about the restaurant down here that caters exclusively to dolphins?”  

“Really? That’s so weird,” Bruce tries, ever the peace-maker.

“Yeah, it only has one customer-- but at least it serves a _porpoise_.”

Clint gags (whether it’s real or feigned is unclear) and Bruce looks regretfully at the deck with his lips pressed together.

Natasha takes that moment to speak up, her eyes still trained on the sea. “Any hits on your device, Stark?”

Tony twirls to face her again, simultaneously checking the tablet in his hand. “Nothing yet, but the fish can’t be far. Everything that Oscorp makes is sub-par, and a mutant sea creature is no exception. We’ll run into it limping around these waters soon.”

The woman snorts lightly and shakes her head. As annoying as he is, Tony is at least trying to make this mission less boring.

Usually an escaped science experiment would classify as below Avenger pay-grade, but recent events considered, they were the first ones called for the case. Lately New York has become something of a zoo; animal-themed baddies with ridiculous gimmicks like “Vulture”, “Rhino”, “Lizard”, and even “Doctor Octopus” have been springing up and proving themselves too unruly for police forces to handle on their own. The only reason they’re on a boat off of Long Island Sound is to corral whatever accidental terror Oscorp unleashed before it can make life difficult for coastal areas.

“World’s mightiest heroes reduced to dog-catchers,” Tony muses mournfully. “You know, I hope the bad press they get from this is enough to finally get Norman out of business. That guy’s sickeningly full of himself. And that’s coming from me.”

Bruce suddenly straightens and reaches for his pocket, withdrawing a buzzing cell phone. He raises it to his ear. “Hey, Steve. Tell me you’re having more success than us.”

The others wait, watching him as he listens to whatever’s being said. Bruce’s tired expression conveys that the soldier isn’t, in fact, having much luck on his part of the mission, which involves talking to locals along the coast to see if they’ve spotted the creature. After a minute, the scientist’s forehead folds in confusion and he says, “Wait, what? He said… well, that’s weird, but not helpful to us. ...Okay, well, we’ll let you know if anything changed on our end. Talk to you soon.”

After hanging up, he looks to the others and explains, “He hasn’t met anyone with information about the thing we’re tracking, but he did meet a fisherman from Kingspoint who said he encountered something weird about six months ago.”

“Weird, like…?” Natasha prompts.

“Uh.” Bruce scratches his head. “The guy just said he was out fishing in a storm and his boat got overturned and he didn’t have any way to call for help, but he hit his head or something and woke up on the beach. Said he thought he was ‘saved’ by a sea creature.”

“Oh, that’s so Little Mermaid,” Tony jumps in eagerly. “Now, that’s a good one. Classic Disney animation right there. Ooh, guys-- what did the mermaid wear to math class?”

“Nobody answer!” Clint orders. “Nobody say anything!”

Tony pouts. The boat rocks in the wind.

Then: “An algae-bra,” Natasha says quietly.

“I’ve never been more disgusted with you guys in my life,” Clint moans over Tony’s delighted laughter.

At that moment, the device still in Tony’s hands begins beeping shrilly. His laughing cuts off as he gives it his attention.

“Alright, ladies, we’ve got a fish!” he exclaims, quickly making his way to Natasha so she can take the screen and steer the boat in the right direction. He then hurries to the high-tech netting device he’s got set up at one end of the boat and begins lowering the traps into the water in preparation.

“Are you sure it’s not a dolphin or something?” Bruce asks anxiously, watching Tony’s activity.

“Sure as sugar, Science Bro,” the billionaire affirms. “I designed the radar to pick up creatures with abnormal genetic make-ups, so ordinary fish and whales don’t register.”

“It’s coming towards us on the starboard side,” Natasha calls.

“Alright, if this invention works the way it’s supposed to, and they usually do, then-- gotcha!” The line goes taut, and immediately Tony hits the combination of buttons that starts it reeling in the net.

The boat goes silent as everyone watches, waiting. Suddenly, however, the mechanism jams and grinds to a halt. Tony frowns and leans over the rail, a hand shielding his face from sunlight as he tries to discern the problem.

“What’s--” Clint starts, but he’s cut off when the boat lurches like it’s been pushed against. Everyone staggers with the movement, grabbing hold of things to get steady.

“Tony, there’s something you should see,” Natasha says, her eyes flicking between the man and the tracker screen in front of her.

Tony doesn’t seem to hear her. “That little fish butt is messing with my tech,” he mutters, fiddling around with the controls. With a whine, the jam comes unstuck. The net raises fully out of the water and the crane swings it around and releases on the deck.

It’s empty.

A giant hole has been ripped through the rope mesh.

“Nope,” the billionaire declares. “No, no, no, sir, I am _not_ being outsmarted by Nessie. It’s war now.” He strides briskly across the deck and retrieves a new net, this one clearly a mesh of his own design. It’s woven with metal and tiny, harpoon-like barbs. Using force was Plan B.

As soon as he’s removed the ruined net and set up the new one, they all can see how much more menacing it is compared to the previous net. Tony lowers it into the water.

“I’m not sure it’s gonna fall for the same trick twice,” Bruce says.

“Oh, this isn’t the same trick,” Tony assures him. “The ordinary net waits for its prey; this one seeks it out.”

“Tony,” Natasha says again, coming over. She holds up the device. “There are two of them.”

Clint perks up. Bruce leans over and squints at it. “Huh?” Tony asks.

“There _was_ just one,” she explains, reversing the footage to demonstrate what she’s saying. “And you caught it in the net. But then another one came in and did something that set the first one free. Now the original is out of dodge, and the second is hanging around. The one that was strong enough to break its friend out.”

The line goes taut again.

“You got those tranqs ready, Legolas?” Tony asks, his eyes flitting between the reeling net and the shaking frame of the boat. The creature is fighting back.

The super spy nods wordlessly, stepping closer with an arrow notched, sea sickness forgotten.

A particularly rough collision jolts the boat and then the rocking stops. They hold their breath at the sound of _whatever_ it is breaking the surface, the mechanism lifting until a dripping bundle is swinging around to face them. There’s clearly something inside this time but its features are obscured by the thick mesh. Tony can just make out the glint of iridescent scales.

As they watch, the bundle is dropped on the deck in a heap. It doesn’t move.

“Is it- did we kill it?” Bruce asks. He takes a step forward, but Tony throws his hand out in a ‘wait’ gesture. The billionaire puts on the Stark glasses that have been resting on the top of his head.

“FRIDAY?” he asks. Immediately his vision is illuminated with a diagnostic scan of the creature, its vitals popping up and indicating unconsciousness. The AI outlines its form and its then that Tony sees it for what it is. He blinks a few times.

 

_No way._

 

Natasha watches his face carefully. “What? What is it?” she urges calmly.

“Uhhh…” Tony huffs a laugh, shaking his head. Instead of answering, he stalks forward and crouches by the mouth of the net, finding the fingerprinted release button there and pressing it. The others make aborted noises of protest as the sealed top loosens, but Tony just moves around to the opposite end and drags the mesh away to reveal the thing within.

“Tell me I’m not the only one seeing this,” Tony prompts, gesturing to their catch. Now that it’s exposed, the man removes his glasses and drinks in the sight with his bare eyes.

 

It’s a kid. A teenager, by the looks of him, no more than 15 or 16, with curling brown hair plastered over his forehead and eyes. He lays there prone on his side, covered in cuts- some shallow, some deep, all of them most likely caused by the barbs on the net. Tony can just make out blood matted on the back of his head- he probably hit it on the side of the boat and got himself knocked out. Clinging to his torso is a soaked, faded t-shirt and below that…

...below that, his lower body is a tail.

A full-on fish tail.

The main body of it is a deep blue, but the broad forked fin at the end fades to a vibrant red, the same as his dorsal ridge and pelvic fins.

 

Tony finally looks up. The others look as dumbfounded as he feels.

“Remember that time I brought up The Little Mermaid?” he asks mildly.

Bruce coughs. He looks the least confused, but it’s probably because the scientist in him is putting his shock on hold- in fact, the dominant emotion on his face is fascination, and he approaches cautiously across from Tony and kneels down to get a better look.

“Well, he’s alive,” he says after a moment, feeling the boy’s pulse gently from where this kid is sprawled on his side. Suddenly he pulls his hand back and squints at something, leaning in and whispering an awed expletive. “Tony, look at this.”

Tony rounds to his side and looks where he’s pointing. On either side of his neck just under his jaw, there are what look like flaps of skin, like they’ve been carved there for ventilation. They’re shuddering minutely in time with each of the boy’s breaths.

“Gills,” Bruce supplies.

“But he’s gotta have lungs in him too,” Tony says. “He’s breathing air right now.”

“Exactly. A duel respiratory system, isn’t that something? I wonder if he-”

Natasha interjects, “Not to rain on the ‘Science Bro’ parade, but the _merperson_ is bleeding out.”

Both their heads snap up to look at her. She’s examining the boy’s- er- tail. Tony cranes his neck and sure enough he sees a long gash torn into the flesh of his flank, running all the way down to wear his knees would be. The salt water pooled around him is steadily darkening with crimson.

Tony and Bruce look at each other.

“Ever sewed up a fish before?” Tony asks.

Bruce shrugs. “There’s a first for everything, I suppose.”

“First aid kit’s below deck, so… who wants to carry him?” Tony asks, looking around. “Clint, you’ve been awfully quiet.”

The agent hasn’t moved since the teen was revealed except to lower his bow and arrow. His face is stuck in a hilariously perplexed expression. “Sorry,” he manages. “Am I the only one still processing that we accidentally caught a _mermaid_?”

“Mer _man_ _,_ ” Bruce corrects under his breath.

Clint continues, “I mean, it feels like we’ve walked into one of 5-year-old daughter’s daydreams, that’s all I’m saying.”

“Lila will be ecstatic,” Nat agrees. “But not so much if she finds out you let him die. So.” She moves to the stairwell leading to below deck and lifts the hatch, gesturing and raising an eyebrow.

Clint shakes his head, muttering unintelligibly to himself as he positions himself by the boy’s lower half. Tony slips his arms under the boy’s armpits and lifts his upper body at the same time that Clint picks up his tail and makes a face. “The scales are slimy,” he whines to himself. Bruce laughs disbelievingly as he follows the procession under deck.

 

…

 

In the tiny med room they’ve got set up, they lay the kid down on a table by the wall and Bruce gets to work finding the proper supplies. The room is pre-stocked for minor injuries-- they weren’t expecting much from this mission-- but what they’ve should work fine.

The lot of them are quietly gawking at the kid’s tail now that it’s spread out on display; the scales are softer and paler on his underbelly, gradually growing darker and tougher as they descend his body and wrap around his backside, tapering off again where the silky material of the caudal fin begins. Out of the bright sunlight from before, it’s also clear how torn up it is. The gash on the left side is the biggest and deepest, but tracks are torn all over his body where the tiny harpoons caught him in his struggles. As they track their eyes up the length of him, it’s quickly obvious that one of his wrists is either broken or sprained, twisted at an odd angle and swelling darkly.

Bruce dampens a cloth and wipes the biggest cuts clean to get a better looks before picking up a small scalpel. “First thing first, there’s a barb still stuck in his side. I’m gonna need to remove that before sealing anything. Tony, help me?” The billionaire nods and moves forward to assist.

It’s at that moment that the creature gasps, his eyes snapping open. To an onlooker it might’ve seemed comical how everyone jumps at the same time, the superspies’ hands reaching for their weapons on instinct, the scientists freezing.

Nobody breathes as they watch the kid's eyes blink a few times, his forehead wrinkling in confusion as the ceiling comes into focus above him. Tony can already see how his pupils are blown, most likely concussed. His eyes dart around the room and take in the four strangers crowded around him on the table, and then to the surgical tools and the knife in Bruce’s hand.

 

They don’t have to be mind-readers to see the wrong dots connecting in his head.

 

“Gah!” he yelps, jack-knifing upright and scaring the tense adults for the second time. The movement must bring his injuries to his attention because he gasps, looks down at himself, and then gasps again, and again, and then he’s full-on hyperventilating. He throws out his good hand to clutch the wall, tugging himself against it and facing the others with a terrified expression, his wide eyes incredibly expressive. “Pl-plea-please-”

“Careful-” Bruce tries, reaching a hand out in concern for the mer-kid now aggravating his wounds. He stops, shocked, when the boy suddenly _backs up the wall_.

“Stay back!” he warns, and the words sound anything but threatening. Somehow the fingers he’s got on the wall are sticking like velcro, holding his torso aloft so that he’s at their eye-level, his tail still draped over the table but tense and curled defensively. "Do-don't t-t-touch me or I- I-" His gaze is growing glassy in panic, his breathing not slowing down. 

“Should I use that tranquilizer now?” Clint mutters.

Now, in his years as Iron Man, Tony has become intimately familiar with panic attacks... He’s sure he’s not the only one here who gets them, it’s kind of an occupational hazard at this point, but what he can say for himself is that they’re hell. They’re on their own unequivocal level of suckiness. Looking at this kid, his thin chest heaving, his eyes seeing but not seeing, he feels his own chest ache in sympathy and remembered pain.

He doesn’t really know, hasn’t had a lot of time to think about, whether or not a merperson should count more for the ‘mer’ or the ‘person’... and Tony’s never been particularly knowledgable about how to calm a wild animal. Has never needed to, but calming a person? That he does know... from personal experience. 

Standing behind Bruce, Tony can see Nat and Clint looking at each other like they have no idea what they’re supposed to do, and that’s when he makes up his mind to give the benefit of the doubt, and he takes the reins.

“Out,” he orders, ushering the spies to back up. “Go check on Spangles or something. You-” he puts a hand on Bruce’s shoulder and guides him away from the table, “-give us some space. Just stay back for a sec.”

They don’t argue. Clint and Natasha disappear up the stairs, casting curious glances over their shoulders as they go. Bruce quietly backs into the corner and looks between Tony and the kid expectantly.

Tony takes a deep breath and turns back to the merboy. The kid’s eyes latch onto him as he takes a cautious step forward. Pelvic fins flutter anxiously and Tony uses a substantial amount of willpower to ignore that, ignore the tail and just keep eye contact and focus on the human half.

“Hey,” he starts, speaking slowly and filling his voice with as much firm reassurance as he can. “Nobody’s gonna hurt you, okay? We just want to help. Can you take some deep breaths for me? Like this.” He puts a hand over his own chest and bodily exaggerates an inhale.

While Tony speaks, the merboy doesn’t look away from the man’s face. Tony’s ‘white flag’ seems to register because his active panic starts dampening somewhat. The arm plastering him to the wall is trembling and he clumsily slips himself back to an upright seat on the table-- whether because he really meant to, or his arm just gave out out of weakness, is unclear-- and raggedly does as he’s told, gulping air in time to Tony’s example. Air whistles faintly across his gills on each exhale.

Tony offers a placating smile. “There you go… you’re alright. Nothing to worry about here.”

They study each other in the wake of tentative calm, the long minute and a half or so where the pair do nothing but breathe and look, and something like curiosity wells amid remnants of trepidation on the boy’s face. He wets his lips and speaks his first coherent sentence, tone utterly perplexed, “Aren’t you- are you _Iron Man_?”

The billionaire’s smile broadens and he looks over his shoulder at his companion. “Brucie, did you hear that? I’m famous in Atlantas!” Turning back to the kid, he says, “Yeah that’s me. Though I prefer to go by Tony whilst out in street attire. Or boat attire, I guess. How about you, got a name? I’d hate to keep calling you ‘fish-butt’ in my head.”

The kid gives him a look, eyebrows furrowed like he’s confused, even offended. It’s not the laugh Tony might’ve hoped for, but if some more of the tension leaks out of Merboy’s posture, he’ll take it.

Merboy holds the startling expression for a moment without saying anything, then it smoothes and his eyes flicker to Bruce and back to Tony. He says nothing, lips pressed shut.

Tony raises his palms in a surrender gesture. “That’s cool, that’s cool,” he relents. “That’s not a big deal, I like my nicknames. Here’s the more important thing: we kind of skewered you with our net… just a tad.”

“A tad?” Merboy repeats, looking at the swelling wrist cradled in his lap, the gash in his tail where scales are missing or slick with blood.

“I mean, it is partly your fault for messing around our ship,” Tony adds, to which the kid looks like he might open his mouth and argue, so Tony goes on, “But that’s neither here nor there, as it wasn’t either of our intentions for what happened to happen. Given the guarantee of no dissections, will you allow my doctor friend to take a look at you? Brucie is a nice guy...most of the time.”

Bruce steps forward, casting a nonplussed look at Tony. To Peter, he offers an awkward wave and a smile, his demeanor as small as the Other Guy is large. “Hey there. I’m Dr. Banner. I’m not technically a medical doctor, but I’m the best we’ve got and I’m worried about you losing any more blood, so with your consent I’d like to help out.”

The kid fiddles with the drawstring of his shirt-- which, Tony realizes, is actually a hoodie with the sleeves cut short-- and says with eyes averted, “I don’t really have a choice, right?”

“Right,” Tony says, at the same time Bruce says, “I’m afraid not.”

And that does make Merboy laugh, even just a small breathless noise that isn’t real humor. “Okay then.”

“I’ll try to tell you everything I do before I do it,” Bruce says, picking up his instruments again. “To start, if you could go ahead and lay back, that’d be great.”

And the kid swallows but does so, looking wary.

Bruce feels for the kid’s pulse on his good hand and frowns. “I know it’s hard, but I need you to try and relax, okay? You really are safe. I’m gonna start by removing debris and suturing the biggest cut.” Over his shoulder, Bruce gives Tony a pointed look that says ‘keep talking please’. Tony nods and drags over a stool.

“So, Fish-butt,” Tony begins, sitting down and watching his friend pull on latex gloves. “We’re looking for a sea serpent around here… got any ideas where it might be?”

The teen looks at him, wincing slightly as Bruce begins his ministrations. “Huh?”

“There’s a laboratory nearby called Oscorp,” the genius explains. “They were doing animal testing and released something out here last week. That’s why we’re here, trying to find it before it hurts anyone. Have you noticed anything whilst swimming around, doing your merperson thing?”

Recognition dawns in the kid’s eyes. “You mean R2? She wouldn’t hurt anyone!”

“R2?” Tony repeats.

Peter blinks up at the ceiling as he explains, and his voice wavers only slightly as he gets going. “Yeah, like... You guys caught her in your net before I- anyway, she’s- well, I don’t know what she is, but I would think she’s what you’re looking for because I’ve never seen anything like her. She’s… maybe part manatee? But seriously, R2 is harmless. Eats sea grass. Makes these little beeping sounds like she’s trying to talk to you. She’s good company honestly.”

Beeping sounds… R2-D2?

Tony and Bruce share a look. _Are we gonna believe that?_ Bruce seems to ask. Tony quirks a brow: _We’re talking to a mermaid, I don’t know what to believe anymore_.

Bruce shrugs and mumbles, “Hey, I’m gonna start applying butterfly bandages to the cuts on your arms and torso. Can we get your shirt off?”

Merboy blinks and looks up at him. “Uh, sure…” He moves to help, but uses his hurt hand on accident and cringes, “Ow.”

“You’re good, don’t move,” Tony assures, closing in to roll the fabric up from his waist. It’s the first time they’ve seen where the skin meets the scales of his tail, and he sees that Merboy’s torso that is basically human-looking, belly-button and all.

What startles Tony most are the scars.

Lots of scars, and they’re not necessarily obvious, but because they’re looking for injuries already, they see them: thin, faded white lines criss-crossing on his sides, his chest, his shoulders and arms. Tony has to do a double-take to convince himself they’re not some sort of merperson markings.

From the way Bruce’s hands still a moment before continuing, he knows they both see.

Merboy is oblivious to the scrutiny, more concerned with the ruined state of his article of clothing. When it’s off and placed nearby in a crumpled heap, he looks over at it with dismay, stains and all, and whines to himself, “Aw man...” Tony has to wonder if he owns much clothing, or whether he even needs to, what with living under the sea. Maybe he snatched the thing off a clothing line hung too close to the ocean for its novelty value.

The kid crosses one arm over his middle and shivers with exposure, looking all-around miserable. That’s when he finally notices the stares of both men, and he tenses, eyes going wide. “W-what?”

Jumpy, like he thinks they’re going to change their minds about dissection at any moment. Tony can’t blame him...it’s a fair concern, if they were any other scientists. Plus whatever left scars like these has got to have left other kinds of scars. Unseen ones.

Maybe best to go easy for the moment, work up to getting answers out of him. (Because that’s just good tactic, Tony thinks; it’s not at all because the merkid is looking more and more like a kicked puppy).  
  
“Nothing, just… nothing,” he assures, waving a hand at Bruce to continue. “Say, Fish-butt, we’re not gonna get in trouble with your folks for this, are we?” The kid tilts his head, so Tony elaborates, “Your people. The merpeople of Atlantis. Atlantica? You gotta help me out, the only cultural knowledge I got about this--” he gestures to the tail-- “is from fiction. Not the best source. Still I imagine it’s not super kosher for humans to be messing with you, right?”  
  
“Oh… no, it’s just me,” Merboy answers matter-of-factly, but then winces like he’s not sure he should’ve said so. Tony pretends not to notice.

“And given your naming from before, I’m guessing you’re a Star Wars fan? What do you think of the new movies?” he asks. Setting aside the need for explanation on how a person living underwater can watch TV at all. One thing at a time.

The kid’s eyes go round, fanboy-style. “There’re new movies?!”

Tony squints at the ceiling in thought. “I mean besides the OGs, I think there’s three? But- actually I think a fourth just come out. It’s the one about Han Solo, right Bruce?”

“Solo,” the doctor affirms, not looking up.

“Darn… that sounds so cool,” the kid says, closing his eyes.

“Oh, and we heard something interesting from a fisherman at Kings Point,” Tony presses without skipping a beat. “He said something about, what was it-- a ‘sea creature’ has been rescuing seamen in distress. You don’t happen to know what he was talking about, do you?”

Merboy’s eyes snap open. Tony raises his brows.

The boy opens his mouth, but all that comes out is, “Uh… no? I mean, I- I don’t-” before he bites his lip and mumbles, “I don’t know what you want me to say…”

Kid’s deception skills are practically nonexistent, that much is clear, but the attempt is endearing. It’s also enough of an affirmative for Tony, and the man has never been great at keeping his curiosity to himself.

“Why?”

The merboy just looks at him, eyes uncertain.

“I mean, is this something you do often?” Tony presses. “You seem to have, like, decent intelligence-- no offense, it’s my first time meeting someone part fish-- so you can see how there’s danger if you’re caught, right?” He doesn’t need confirmation; he remembers Merboy’s immediate reaction to the surgical instrument in Bruce’s hand. “...So what’s the M.O.?”

Kid sucks in a breath, looking away. “Okay, I wasn’t gonna say anything, but my head actually, really hurts? A-and, I haven’t been having the best day today, so if we could just…not…”

Bruce clears his throat, drawing their attention. “No wonder your head hurts; I suspect you’ve got a mild concussion. Don’t mind Tony.” Tony huffs but Bruce pays him no mind. The doctor sets his things down and backs off, folding his arms and leaning against the wall. “I’m mostly done, it’s just that- well, the wrist. I don’t have the tech or the materials to do an x-ray or set a cast.”

The kid is already pushing himself up on his elbows, good hand bracing the wall and _velcro-ing_ again as he pulls upright. “That’s fine,” he says. “I’ll be okay, thanks for everything-”

But Dr. Banner scratches the back of his neck uncomfortably. “Er, not to be rude but-- your injuries…I don’t know how your physiology works _usually_ , but I don’t think I can in good conscience toss you back to the ocean in this state. For one, those cuts will open again if you move around too much. For another, your wrist could heal wrong and then you’re stuck with it.”

Merboy considers this, his eyes flicking between them. “Sooo...that means what, exactly?”

“It means,” Tony catches on, “that unless your Fish-butt wants to go out back there looking like a shark chew-toy, you’re gonna need to come stay at the Tower for a few days at least. Secretly, of course.”

Going by Merboy’s spooked reactions so far, Tony would’ve thought the news would freak the kid out. On the contrary, his eyes light up and his mouth falls open.

“Hang on. ‘The _Tower_ ’?” he asks. He looks at Tony. “Like, Stark Tower? Where you live?”

“No, the Tower where _another_ set of superheroes live,” Tony deadpans, rolling his eyes. “Yes, kid, the one where we live. You do know you’re on a boat with the Avengers, right?”

“Wait, what? You-“ Merboy gapes. “You’re the- those other people were--?” He slumps and goes still. “Oh my gosh.”

Bruce smiles. “There’s a private med bay there so we can keep you hidden. And then we can have you back in the ocean as soon as you’re healing up, I’d guess in a week or so. Deal?”

There’s a pause like a held breath, while they wait on the answer. Merboy’s eyes wander to his crumpled hoodie… he takes a deep breath, and nods.

“Woo,” Tony cheers quietly. Bruce looks relieved himself, and pushes off the wall to head for the exit. “Okay, I’ll just go tell the others the plan,” he says. “Just rest and- yeah.” With that he disappears up the stairwell, leaving them alone.

 

Tony looks at the kid.

The kid looks at Tony.

 

“Um…” Merboy’s pelvic fins flutter again, and Tony thinks the action is probably a nervous tick. “I- I hope it’s not- I-” He stops himself and tries again. “I’m sorry you have to take me with you guys.”

Tony tilts his head. “I am a billionaire-slash-superhero, kid. Having a merperson as a guest isn’t even the most inconvenient thing to happen to me this week. Not that this is inconvenient at all. Interesting, though? Yes. I am interested.”

“You’re taking it pretty well,” Merboy nods. His gaze flits around the small space and he swings his tail a bit. “All things considered, if I had to get caught, I’m glad it was… not anyone else.”

Tony hums. He reaches over and picks up the ruined hoodie, appraising the weathered fabric as it drips seawater on the floor.

“I can get this washed,” he offers. “Or get you a new one, altogether, seeing as the thing’s kind of a mess.”

The kid huffs a self-conscious laugh. “Yeah, yeah it’s pretty old. I should probably give it up. As for a new one, that-- that would actually be really great, thanks.”

“No problem, Fish-butt.”

The mer-kid finally cracks a smile. It’s small, maybe still guarded somewhat, but it’s one of the brightest things the billionaire’s seen. He’s reminded of a line from a poem he heard somewhere, though he couldn’t have said where, but it sounded cheesy and fortune-cookie-esque at the time: _The saddest people smile the brightest. The loneliest people are the kindest._

There’s definitely more to this teen than meets the eye-- and there’s a lot that meets the eye, all things considered (hello, fishtail and gills).

 

“Peter.”

 

Tony blinks at the sudden word. “Hm?”

“My name,” Merboy clarifies. “It’s Peter. I thought you should know.”

Peter. That’s… shockingly ordinary, for a mythical creature, Tony thinks. Not that he knows what merpeople ought to be named. He leans forward, because it seems like more is on the tip of _Peter’s_ tongue, so he prompts, “Yeah, it’s useful.”

“And...I like to help,” the kid goes on surely enough, his expression and body language shy but earnest. “That’s why…I mean…what you asked earlier? I just think- well, I think that if I have the opportunity to help and I do nothing then, whatever bad thing happens is on me, right?”

Tony lowers his gaze, absorbing that. A blend of emotions stirs in his chest, not the least of which is something like respect. Respect for this baby-faced mer-kid who just spewed a bit of wisdom that took Tony years to acknowledge. Young as he is, he’s applied that wisdom to the best of his ability and, yeah, is probably still hiding things, but already Tony can tell he’s a decently pure soul nonetheless.

A soul who would almost certainly be caged and studied if the world found out about him.

“Nice,” he says.

 _I’m keeping this kid under my protection_ , he thinks.

...

...

...


	2. testing new waters

**Notes for the Chapter:**

> Sooooo  
> In this AU, Obadiah is still a greedy little slut and was selling weapons behind Tony’s back (and Tony didn’t ever fully find out), but he didn’t go berserk and make an Iron Monger suit/steal Tony’s arc reactor etc u get me
> 
> (if I’m gonna make Spider-Man a merperson,,, I might as well change whatever else i want bc #fanfiction amirite)
> 
> Art for this chap by my Big Bang partner, the lovely fanaticfangirl2602, can be found [here](https://fanaticfangirl2602.tumblr.com/post/183438707582/my-second-piece-for-the-reverse-mermaids-sea)!

…

…

…

(Peter dreams in memories sometimes.)

 

_He woke in a bed of fronds somewhere deep, a surface like rippling glass high above him and casting light like a heat mirage on the duller tones of navy and green. He wondered at first if he wasn’t still asleep, caught in an odd in-between state of dreaming and awake._

_He opened his mouth to call for Ben or May, to ask what was going on, but the sensation of salt water rushing in, suddenly cold on the walls of his mouth, had him startling upright, mouth shutting but eyes opening wide. Everything was crystal clear, not even murky or stinging like seeing underwater usually is… and that was where he was. He was underwater._

_One time at Ned’s house, Ned’s mom had taken them and Ned’s little sister to go swimming at their apartment clubhouse. Ned had goggles with snorkels attached that he let Peter use to keep his head underwater and breathe air at the same time, and it made Peter feel like he had a superpower._

_He didn’t have a snorkel on right now, and he was breathing underwater. Or was he? His chest was rising and falling, but it wasn’t his nose or mouth getting the air...he reached to where there was a strange sensation on the sides of his neck, and felt weird things there that he definitely didn’t remember having._

_An actual fish swam by his face, tiny bubbles flitting in its wake, and Peter blinked and tried to think what he did remember. Then he wished he hadn’t._

 

_Screeching tires. A crash. Waking up in a bed and a stranger sitting there to tell him he was alone._

 

_And then running- and then falling- and now-_

_Peter looked down at himself. He still had his uncle’s hoodie on, but his legs...his legs were gone. He moved as if to flick his toes, and the tips of a scarlet caudal fin waved back at him._

_That was just the first day, and all Peter could do was lay back down in the seagrass, blinking upwards for hours, until the light faded and he fell back asleep in the gentle sway of currents._

_Days, months, years later… he’s still alone but he thinks he may have made a friend, now. It’s a sea animal like one he hasn’t met before, not stuck-up like a dolphin or rude like a shark or intimidating like a whale._

_He was swimming in one of his favorite spots closer to the cliffs, scanning half-heartedly for interesting debris like he does sometimes, when he sensed movement and turned to see her whiskery snout grinning at him from a ways off. He’d tilted his head, thinking she was the biggest seal he’d ever seen, but when she turned he saw a set of reptilian legs and a swaying gator-like tail paddling her along, and he couldn’t resist laughing, sending a stream of bubbles skyward._

_She let him pet her leathery tough scales, nuzzling into him just as easily with trills like beeps rumbling out her snout, and followed him around like a puppy after that. Peter thought they made a good pair… “It’s a mystery how either of us got this way, but here we are- odd mixes of things,” he’d told her when they surfaced in his cave. “That means we gotta look out for each other. Right?”_

_R-2 just trilled._

_All too soon, her trills were ringing out frantic and scared from inside a fishing net._

_It wasn’t hard for Peter to yank back…to tug-of-war with the device reeling his only friend away from him. He gripped on and tore a hole in the mesh, big enough that R-2 swam out and she waited nervously for him. Peter just shewed her on, wanting her out of there, and he would have followed had he not heard something that caught his attention._

_Words were indistinct, but there was a voice in his memory Peter would never forget._

 

_(“Nice work, kid.”)_

 

_He paused to listen, and that’s why it got him._

_In the back of his mind, the part that was annoyingly calm and sarcastic no matter what, he thought that the barbs digging into his flesh all over were a perfect symbol for the fear simultaneously gripping him with sharp claws. He thrashed, tail slamming the side of the boat, but somehow his hand got caught in the mesh and it twisted with his struggles. The water muffled his cry and he grit his teeth, rammed his head backwards in frustration and-_

 

_Lights out._

 

The dream shifts.

 

_He’s 8 years old, riding on his uncle’s shoulders so he can see above the swarm of people, and through the slits in his homemade Iron Man helmet his eyes are wide with excitement at everything Stark Expo 2010 has to offer._

_When drones attack and in the midst of running and screaming, he’s separated from his family, Peter is not as scared as he probably should have been. A robot lands in front of him and he raises his palm like he’s seen his hero do on TV and—_

 

_“Nice work, kid.”_

 

_—He’s safe._

 

_…_

 

Peter comes to with a start.

 

Blinking blearily, he sees that it’s twilight outside and down in the belly of the ship it’s almost too dark to see. Normal eyes probably wouldn’t be able to see. As for Peter, he’s seen his eyes in the reflective surface of seashells and broken glass. Ever since what happened happened...not only does he not need glasses, but his eyes glow like a cat’s in the dark.

(It scared him at first.)

For the second time today, Peter is confused by finding himself out of water, and it takes a moment of looking around and searching his recent memory to stop a second panic session.

Caught in a net like an idiot…check. Maybe it’s not fair to berate himself, considering the net itself attacked him like a weapon. His throbbing body attests that. But, he knows better than to hang around a ship unless, like, someone is drowning. When someone is drowning then he’s definitely there.

“ _You can see how there’s danger if you’re caught, right? So… what’s the M.O.?”_

Vestiges of his dream come back to him, along with fresher memories.  

Iron Man was here. _Tony Stark_ was- he was really _here_.

Peter groans and stuffs his good hand into one eye socket because wow… he really made an idiot of himself in front of his childhood idol, didn’t he? Not that the man would _know_ that’s what he was, because he’s apparently thinking Peter was born like this when he wasn’t. Seeing as the man’s a genius, though, he’s bound to have noticed some discrepancies. Peter really can’t keep secrets to save his life, and add panic and a concussion to the mix…

As if sensing the merboy’s return to consciousness, someone from above makes the boat creak as they make their way down the steps to his room and flip a light switch.

Peter blinks, squinting in the sudden light and finds himself face-to-face with the Iron Man himself once again.

He sits up straight. “H-hey!” he says. Because he’s eloquent like that.

“Hey,” says Tony freaking Stark, cracking a smile that is no-doubt at Peter’s expense. Peter feels his face heat up. He ducks his head.

The boat lurches a bit and with it, Peter’s stomach rolls. “Ugh,” he moans to himself, moving his good hand to clutch at his middle.

“Woah, what’s up?” Mr. Stark asks, immediately on the alert. He descends further into the cabin and approaches the table whereon Peter lies, hands lifting as though ready to assist. “Something hurt? Did we miss an injury?”

Peter peeks an eye open and grimaces. “No, it’s nothing, it’s just… I’m a little seasick,” he admits.

A pause. “Wait,” Mr. Stark says, hands lowering. “Wait, how does a _merperson_ get seasick?” There’s definitely amusement coloring his tone.

Peter has to level a mild glare at that. “Swimming and being in a boat are completely different experiences!”

“Sure, true,” Mr. Stark concedes, still grinning. “Bruce actually has some stuff for nausea with him so… I can get you some of that. I came to say that we’re gonna start heading back to shore now that the sun’s going down.”

A thrill rises in Peter’s gut that has nothing to do with seasickness… more like the nervous energy he would feel before his turn to answer a question in the junior high decathlon team he was on for only a brief amount of time.

Right- he’s going to stay at the Avengers’ house for a sec. Cool. Awesome. No big deal.

He clears his throat and nods once, leaning his head against the wall because he may or may not feel a little faint. “Right,” he says. “I’m ready. Let’s do this.”

Mr. Stark regards him curiously.

Peter shivers, still feeling exposed all over without his dilapidated but familiar hoodie. He’s hardly thought as much before Mr. Stark is striding over to the thing where it’s hung up to drip dry and feeling it in his hands.

“This is still a bit damp, but I’m guessing you don’t mind?” he says, holding the article out to Peter, who takes it gratefully. He shoves his nose into the fabric out of habit… it definitely no longer smells like Ben, and the cotton has shrunk considerably from salt water exposure, but it’s still a tie to his family, a piece of them that he has left.

Quickly he burrows in, being careful when sliding his hurt hand through its cut-off sleeve. “That’s better, thanks,” Peter says, tugging at the wrinkles in the fabric. He looks up...Mr. Stark is still watching him. “Sheesh, you guys like to stare at me…” he mutters before he can think better of it.

Mr. Stark just laughs and turns to the exit. “I’ll get your ginger stuff, fish-butt,” he throws over his shoulder before starting up the steps. Peter watches him go with warmth settling in his chest. It takes him a minute to figure out why: the teasing, the caring...it reminds him of May and Ben.

He shakes his head.

It’s been awhile since he’s been around people, sure, and it’s _so cool_ to be meeting the Avengers...but there’s no way he’s projecting his issues onto Tony Stark. As if anything could come of it anyway.

 

…

 

“Okay, is anyone going to tell me what’s going on?” is the first thing Steve says when they’re docked thirty minutes later and the man meets them on the peer.

“Maybe,” Tony says, leaning over the rail to look at him. “Did you bring what we asked?”

Steve huffs but nods, stepping aside so they can see more clearly the wheelchair he’s got beside him, a pale yellow scarf and blanket folded neatly in the seat. Tony looks over it approvingly before motioning for Clint to follow him below. The two men disappear and Bruce, Nat and Steve look at each other.

“I’m very confused,” Steve states after a moment. “Did you find the creature?”

Bruce smiles apologetically. “No, actually, it turns out that’s not even a problem. And, uh, we were confused too but trust me-- it’ll be easier to believe when you see him.”

“Him?”

Clint and Tony reappear, something cradled between them, and a startlingly young voice chirps out, “Dude... that’s- is that...?”

Steve peers through the dark to see him-- a young teenager being held by the men in a two-handed seat carry. He can’t discern much about his appearance but his eyes, locked on Steve, are wide and shining with a mixture of shy excitement (and possibly glowing a bit, if that’s not a trick of the moonlight).

“Don’t get too starstruck,” Tony says. “I know for a fact that the man microwaves his poptarts.”

“So he recognizes you and Cap,” Clint grunts under his breath. “But what are the rest of us, chopped liver?”

“You have to admit, we make the best action figures,” Tony replies, to which the archer has to frown and tilt his head in acknowledgement. “Nat, could you-”

Natasha wordlessly steps forward and pushes the wheelchair as close to the side of the boat as it can get, swiping the items off its seat and standing back. The men count to three softly before hefting the kid over the edge, and, with Natasha’s help from the other side, somewhat sloppily landing him in the seat.

Steve gets it, then. “Oh,” he says, staring unabashedly at glinting scales.

“Yeah, oh,” Clint agrees, hopping over the edge himself and patting the soldier’s shoulder sympathetically.

“Peter,” the merperson says, gesturing to himself by way of introduction. “Cap, Captain, I’m- I’m a big fan.”

Steve can only nod at him, speechless (an admittedly rare occurrence for him).

Tony is already off the boat, and taking the blanket from Natasha. He eyes Steve before draping the thing over Peter, and sure enough it’s long enough to cover Peter from his lap to the tips of his caudal fin, which he has curled under the footrest in a snug fit. Next is the scarf, which Tony takes and wraps loosely about the boy’s neck, though not before Steve gets a startling glimpse of gills.

“Sooo,” the super soldier tries. “Wait a second. What happened exactly? You’re taking this kid home with you?”

The genius glances up as he circles the kid, making sure he’s tucked and covered on all sides. “There’s really not much to get here, Capsicle. We found the kid _._  He got hurt. Now we’re gonna fix him up.”

“You could say I’m getting away from my usual _sea_ -nery,” Peter suggests, then giggles at his own joke. Unbeknownst to him, the other Avengers look at one another and then cast significant glances from Peter to Tony.

Tony himself looks at the back of Peter’s head with a dumbstruck face, but it morphs into something as delighted as a parent hearing their child speak for the first time. When Peter pauses and looks around self-consciously, the billionaire schools his expression.

“And Pepper?” Natasha speaks up for the first time. Despite her unusually soft tone, the name causes everyone to stiffen, especially Tony. “She won’t mind a guest?”

“Dunno...she kinda has other things to worry about,” Tony says curtly. “Anyway…”

He breathes out and meets the confused gaze of the merkid, then takes hold of the handles of the wheelchair and pushes it experimentally. “Let’s blow this popsicle stand, yeah? You’re riding with me, kid. And you better like it cuz I’m gonna need a bunch of air fresheners to counteract the fish smell.”

Peter returns Tony’s look unsurely at first, but the quip draws out a tiny grin. Steve can’t help but notice that the wide-eyed way he looks at Tony… you’d think he hung the stars in the sky. Or put the water in the sea, or something. Point is, there’s trust there already, more so than for the rest of then.

Tony offers a salute before turning and wheeling them both down the peer. The group left behind can already hear the man starting to motormouth commentary to his new charge ( _“Listen, you need to get those stars out of your eyes. I’m not kidding about the poptart thing, and don’t even get me started on how he eats his toast…”_ ) before their voices fade with distance.

“I’ll meet you guys there,” Bruce calls after them. They don’t seem to hear.

“Are we… are we sure Tony will put him back in the ocean?” Clint asks into the silence. “I mean, it’s not like he doesn’t have the money for a giant fishbowl…”

Nat’s lips twitch upward. Bruce shakes his head. Steve continues to process.

 

…

 

On the same evening, an odd pair walks the streets of Manhattan, drawing glances from even the New Yorkers who have long since gotten over seeing strange tourists in their city. The man and woman don’t seem to care about the attention; their focus is entirely in mapping the city and conversing with one another in quiet, furtive tones.

“Calypso, my love,” the man says. He is tall and broad-shouldered, his fiery red hair as long and untamed as his beard. Dressed in animal-skin coat, he could have walked out of a movie about Hercules, except that his accent is something from eastern Europe.

The woman pauses to look up at him, her amber eyes dancing over his face playfully. Her thick, silky hair is splayed over one shoulder like a black waterfall, her skin a rich caramel color in stark contrast against the lavish white cape around her shoulders. When she speaks, her words are lilted, “Kraven?”

“Are you sure there is game for me here? This place, it is… very domesticated.”

She laughs softly, untangling her arm from his and reaching up to touch his face. “Oh, there is something for you here, my hunter,” she purrs. “It is only a matter of time. Do you not remember the reports we received? There are creatures here, and one of them is bound to be worthy prey. Patience, as in any pursuit, is required.”

He reaches up to cover her hand with his own large one, holding it gently. “You are right,” he agrees. “I only wish I had a pelt to gift you with now.”

“Soon,” she emphasizes, grasping his fingers and lowering their entwined hands to swing between them. Her thick collection of beads and bracelets rattle with the movement.

The two continue their walk.

It is about thirty minutes later when, being unused to crowded city streets, they cross a road at an inopportune moment and a car comes to a screeching halt to avoid a collision. In the light of its headlights, Kraven turns angrily to yell at the ‘metal beast’.

Calypso sighs, accustomed to her partner’s outbursts, and turns to pull him along when suddenly she, too, freezes.

By the streetlight she sees an adult man in the driver’s seat of the vehicle, his exasperated face recognizable. He is some kind of inventor-business man, she thinks. Well-known in the Western world. She has never cared much for such things. Behind the man, though, there is a figure huddled in the back seat, his curly-haired head poking out from a blanket wrapped all around him, and it is this one that draws her attention. To the physical eye, he is an average teenage boy with nothing distinctive about him. To her ‘third eye’, however…

The boy is watching the man behind the wheel, but feeling her gaze on him, his eyes slide over to hers and her breath catches because _yes_ , there is definitely magic there. It’s a particular strain that she doesn’t recognize, but it’s surrounding him and it’s _strong_.

Cars are honking behind the stopped car when Kraven’s tantrum finally ends and he stalks out of the road, Calypso quick to follow. She stares after the vehicle with the boy in it until it turns a corner and disappears from view, but even so, a pleased smile spreads across her face.

“Calypso?” Kraven wonders, noticing her fixation.

“Oh, my love,” she returns, taking his hand. “The search is over. I have found something for your collection.”

 

…

 

The ride through the city has Peter ogling at everything, pressed up against the glass window like a small child, city lights reflected in his eyes. Tony tries hard not to be too obvious about watching him bemusedly in the rearview mirror, just talks randomly from topic to topic as they come to mind, mostly about the quirks of his teammates.

Soon enough the big tower with its glowing A comes into view, and Peter’s jaw drops. “Holy crap,” Tony hears him say under his breath.

“Home sweet home,” the man announces. Silent anticipation befalls the car as they drive down into the underground parking, Tony swiftly taking them to his private lot and pulling into a spot. As soon as he’s got the wheelchair unfolded from out of the trunk, he opens Peter’s side door and seizes him up fondly…the merboy is wrapped up in his blanket like a burrito across the backseat. A merburrito.

The kid looks up at him, eyes as wide as ever.

Tony reaches out. “Upsy daisy,” he says, gesturing for the kid’s hands. Disentangling himself from his burrito and scooting forward as best he can, Peter tentatively puts his hands into Tony’s and both brace themselves as Peter is lifted and held to the man’s chest, just for a second, before he's settled in his chair once more. The boy is quick to tuck his tail into the footrest and pull his blanket over himself, glancing around the lot warily.

“Don’t worry, nobody will be on this level,” Tony informs him. “It’s my personal garage.”

Peter nods, eyeing the other vehicles. “That explains the crazy cars.”

“Crazy,” the billionaire agrees, “but definitely fun to drive. At least until you have a bad experience with an angry electric whip guy on a racetrack…” Peter gives him an inquisitive look, but Tony shakes his head, taking the handles of the chair and beginning to push them toward the elevator. “That was kinda my fault. Don’t ask.”

“Why do you even need cars, when you have a suit that can fly you anywhere you want?” the kid says.

The elevator opens, and Tony wheels them inside as he replies, “I wasn’t always Iron Man, you know. Maybe it seems that way to a squirt like you, but I wasn’t. How old are you, anyway, like twelve?”

As expected, that earns an indignant response. “Wha- no! I’m almost sixteen!” Peter pauses. “At least, I’m pretty sure I am…what month is it? I know it’s summer but I only keep track of date by the fireworks on July 4th so...”

And doesn’t that just bring up more questions. Tony has decided that as long as it helps the kid open up in his own time, it’s best to play the “need-to-know”-info-only game. He answers slowly, “It’s June 2018, kid.”

Peter goes distant at that, his face tightening just the slightest bit. He’s staring off at the elevator doors and Tony’s watching his face, and that’s why, when the elevator dings and stops prematurely, the man doesn’t notice anything is off until Peter pulls back into the present with an expression of alarm. Immediately Tony turns to follow his gaze, and he, too, feels apprehension grip him because--

“Obie!” he says, going for casually surprised. “What’re you- what’s up? How’s it goin’?”

The older man is dressed in business clothes, his ice blue eyes squinted at the pair before him, calculating.

Obadiah Stane...the man who was once something of a mentor-figure to Tony, but in the past several years their relationship has all but shriveled. It’s not hard to pinpoint the cause: ever since Tony turned the company around at that press conference, made and stuck to the decision not to sell weapons anymore, and the Stark industries manager realized there was nothing he could do to change Tony’s mind, he had resigned any emotional connection they had and become bitter and distant. And then Iron Man and the Avengers happened, and they saw one another less and less as other people became important in Tony’s life and well...here they are. Practically estranged.

Despite being acceptably within the age of retirement (he's pushing his early 70s), the man still shows up and Tony doesn’t have the heart to kick him out. Even if he is only hanging around out of pride at this point, always reminding everyone that he's the only staff member remaining from Stark Inc.’s early days. Well, pride and profit. The two most important things to Obadiah.

“Tony,” he greets, bypassing Tony’s questions. When his gaze falls to Peter, looking him up and down, Tony feels his hackles raise in defense. “Who’s this?”

Peter’s face looks like that of a deer in headlights, and his mouth opens like he’s grasping for an acceptable answer. Before he can, though, Tony says off the top of his head, “New intern, recruited as part of the September Foundation. I’m going to show him around the labs.”

Obi hums with a tilt of his head, but is clearly less than interested. “Must be something special if he’s getting his own personal tour,” he mutters nonetheless. He finally steps into the elevator across from them and hits a button, and Tony is acutely aware of the five feet of fish tail currently barely hidden in the 6-by-8 foot space that the three of them now share.

“Yeah, his application was pretty impressive,” Tony affirms, meeting Peter’s gaze and giving him a look that conveys, _‘Don’t. Say. Anything_.’ The kid’s mouth snaps shut. To divert attention away from him, Tony says, “So, what’re you up to this time of night?”

Obadiah smiles without humor. “Just a check-up on management, making sure all the little cogs are running smoothly, you know,” he says vaguely. “Someone’s gotta make sure the interim CEO knows what he’s doing, right? It can’t be Pepper, and apparently it can’t be you since you spend all your time with the super-friends now.”

It’s said without aggression, friendly-sounding even, but it’s still biting...especially the pointed reminder about his fiance’s condition.

“Yeah, well,” Tony pushes out, “I thought I’d leave something for you to do, make you feel special.”

“Hmm,” Obi hums again, and the tight-lipped smile on his face feels rotten.

The elevator stops and dings at their level. Finally, Tony thinks, quickly steering them out the exit. He ignores Obadiah's stare as they pass in front of him, thinking only of getting Peter to privacy.

He doesn’t see how, as they bump over the ridge between shaft and hallway, something tiny plinks across the floor, left behind in the elevator. He doesn’t see how Obadiah’s brow furrows, and after they leave, he looks down at the thing that fell out of the boy’s wheelchair, and he thinks confusedly that it looks a lot like a fish scale.

 

…

 

It turns out Peter’s wrist is not broken; it is, however, badly sprained.

He’s not gonna lie, he’s starting to have a hard time keeping his eyes open. The entrance to the tower, the med bay, and the whole situation was just...way more excitement for one day than he’s used to. So when the injury is finally splinted in a fingerless glove-type thing, and Tony has to wave a hand in front of Peter’s face to get him to perk up tiredly, he knows he’s on the verge of passing out.

“Earth to fish-butt,” the man is saying. “Stay in the land of the living for a bit longer, yeah? I need to get food in you before you take this anti-inflammatory med. Anything sound good?”

“Uh…” Peter says, squinting. “Sure, anything is good.”

Mr. Stark rolls his eyes. “Anything in _specific_?”

For the past two years… all Peter’s eaten is what he could get his hands on. So, essentially fish that he has to catch and cook himself (a necessity that was so very not pleasant for him to adjust to), and edible seaweed. One time, a packaged bag of chips floated out to sea and it was still sealed and it was the highlight of his week. Realization dawns on him as he processes the possibilities here. “Oh... _oh_ ,” he says.

“Nevermind, I’ll just order take-out,” Tony decides, apparently done negotiating with Peter’s incoherence. “Let’s just get you in a bed already, geez.”

He starts tapping something on his phone, and Peter frowns. The med bay around them is well-stocked with beds, even comfy-looking beds, but… he just hasn’t been out of water this long before. The reminder has him sweeping the blanket off himself, and sure enough, the tail underneath isn’t doing too great. He runs a hand over his scales, and instead of their usual slickness, they feel dry and itchy, flaking a bit like dehydrated skin. Looking closely at his hands, he taps his fingers together a few times to test their suction-cup-y tips, and they’re maybe less sticky than they should be.

He bites his lip and looks up.

“Mr. Stark? Is there… is there a place I could stay that has water? Like… I don’t know, a bathtub or something?”

Mr. Stark puts his phone down, following Peter’s gaze. “Yikes, okay. No bed, then.” He clicks his tongue and a hand comes up to brace his chin, thinking. After a moment, he claps both hands against his knees and meets Peter’s eyes, announcing, “I got something we can try.”

Ten minutes later sees them at the edge of the biggest indoor swimming pool Peter has ever seen. Also, the _only_ indoor swimming pool Peter has ever seen. It puts Ned’s apartment’s pool to shame, that's for sure.

The space itself is big, wide and lit with pretty ambient lights. Above them, the ceiling is paneled with glass, a window to the night sky with its crescent moon and what few stars are visible this deep in the city. The pool’s water glitters with the reflection, like a second sky spread out before them. The markers along the side announce a deep end of 12 feet, which, sure, compared to the usual hundreds of feet isn’t much, but it sounds pretty wonderfully spacious to someone who has been carted around all day with all the autonomy of a sack of potatoes.

“It’s salt water, not chlorine,” Mr. Stark tells him. “Easier upkeep that way, and an unforeseen benefit for the merfolk guests: you might just be able to breathe it.”

Peter’s hand touches to the scarf at his throat. “Well, no time like the present to find out, right?” He tugs the fabric off, setting it atop the blanket folded in his lap. The bundle gets dropped beside the chair, then he looks down at his hoodie for a second before it, too, is slid off and put aside.

Mr. Stark holds out his arm, and the merboy latches on for support as the chair is pulled away and he’s lowered down to the floor, the edge of his fin draping over the lip and into the water. All it takes it that contact, and Peter feels an instinctual need like burning in his gut pulling him forward like a magnet. Despite Mr. Stark’s hands reaching to assist him in, Peter dives forward and barely catches the man’s noise of surprise as he’s splashing under the surface, completely submerged.

It’s _wonderful_.

The water is clean, which can’t always be said of ocean water, and it’s almost softer in a way, enveloping Peter head to fins like a welcoming hug. He can tell that the water that crosses his gills isn’t normal, it ‘tastes’ a little chemical-y and has none of the freshness of the sea, but sure enough he can breathe through it just fine.

He stretches his good arm out in front of himself and propels around the space gently to settle into it. His injuries pull and throb, reminding him of his fragile state...and so all too soon he reluctantly angles upward and pulls to a rest on a wide shallow step at the edge of the pool. There he props himself on his elbows and breaches the surface with his torso, whipping the drenched hair back off his forehead in one fluid motion. With a contented exhale, he looks up for Mr. Stark.

 

He’s there, sitting with his arms resting on his knees, and the man looks entranced. Actually floored.

It makes Peter laugh out loud. _What did he expect?_

 

At Peter’s laugh, the man blinks and shakes his head, beginning to pull up to his feet.

“I’ll, uh- I’ll be back with food,” is all he says, voice subdued. “Don’t pull your stitches.”

He leaves.

Peter laughs again, turning over and backstroking lazily in the quiet of his new room.

 

…

 

When Tony does come back, a box of take-out in hand, it’s to see the merboy curled up on the seat again, fast asleep with tiny bubbles skimming across his gills as he snores just under the surface.

 

…

 

A wall of light slants across the room from the windows above, and so it’s a streak of sunshine falling across his face that wakes Peter the next morning. Unlike the last few times of coming to consciousness, he allows himself to wake slowly, unwinding and one-handedly scrubbing his eyes with a prolonged upper body stretch. He feels pleasantly rested, and his return to wakefulness is aided by a charge of excitement in his bones because yeah…he’s staying in the _Avengers Tower_. Who even knows what today could entail? (En-TAIL. Hah.)

He pushes upright, breaching the pool water and blinking his eyes rapidly to adjust to the increase in brightness. He feels a bit of a head rush and realizes, yikes: no matter what time it is, it’s certainly been quite a few hours since his last meal. His stomach growls in agreement, and his sensitive nose picks up on food nearby. Turning just slightly, he sees a brown paper bag at the edge nearest him, within arm reach, apparently left there for him. Curious, he reaches for it.

Inside is an apple, a couple of bagels, and a few 2-tablespoon containers of peanut butter.

 _An apple. Bagels. And peanut butter_.

Peter would like to say he hesitated, or, like, thought about it in any way. He doesn’t, though. One second he’s discovering the items, the next he’s devouring them. There’s a plastic knife for spreading the peanut butter, but it’s too slow; Peter sticks his tongue in the container and straight-up licks it out. And holy _crap_ is it worth it.

He is literally through one bagel and half the apple before he notices that he’s not alone. Usually he has a good sense for things around him, but maybe that only applies to being underwater…because something, some _one_ shifts across the room and he freezes, a dollop of peanut butter still on the tip of his tongue.

There’s a man sitting there, lounging in one of the pool chairs like it’s a throne, and looking at Peter pleasantly. He has a distinct look, even dressed casually- the tangles of blond hair falling over his shoulders and scruffy viking beard mark him as someone Peter recognizes immediately, if only from posters he had as a child.

Thor. Norse god of thunder, Avenger, and… evidently, another Peter-watcher. 

“Holy--,” Peter gasps, dropping the apple to the floor in surprise. “Oh, my g...h-h-how long have you _been_ there?”

The man’s grin broadens and he moves to sit forward. “Oh, only about half an hour,” he muses, his voice so deep and regal and _powerful_ -sounding that Peter gulps. “But, I only arrived at Stark’s building shortly before that and I am needed nowhere else at this time, so I figured I would come and see whether Banner’s report was true for myself.”

Banner. Bruce Banner. Also known as, the Hulk; also also known as, the guy acting as Peter’s personal physician currently. “O-oh?” he squeaks, sinking down into the water a bit.

Thor stands and makes his way to the edge of the pool, an actual skyscraper from Peter’s perspective…but then he drops down into a freaking criss-cross-applesauce position, gesturing to the brown paper bag of food.

“I’m glad you enjoy the spoils I gathered for you!” he says brightly. “I, too, am a fan of Midgardian ‘peanut butter’.”

“You- you got me this? Wow, uh- wow, thank you,” Peter stutters. To his embarrassment, his pelvic fins flutter involuntarily like they always do when he’s nervous.

Thor just nods, eyes gleaming. “Of course, you are a growing young selkie! You need nourishment! They tell me you are called Peter. I imagine my reputation precedes me, but in any case, I am Thor, prince of Asgard.”

“Uh.” Peter’s brow furrows, mind catching on a word. “Wait, selkie? What is that?”

The god gestures to Peter and says, “Well, you, of course! The only selkie I have heard of in Midgard for thousands of years! Although, that is just a regional name; where they are found and what powers they possess distinguish them to different cultures. We have a similar race in my home, and in other places in the nine realms that I have heard tales of.”

Peter sits up straighter, hand grabbing hold of a nearby guide rail. He feels his heart climb into his throat, because this- this is what he’s had questions about for so long now.

“Tell me,” he says, before he can stop himself. “I mean, uh- what can you tell me about, like, selkies in general? Are they all the same?”

“In some ways yes, in others no,” Thor answers, his sky-blue eyes looking afar off in recollection. “Their origin is perhaps what most have in common. I do not know a great deal on the matter, but I know there is ancient magic associated with the oceans in each realm, magic which is thought to be sentient in nature and thus particular in who it chooses.”

“Chooses, like… chooses to turn them into...”

“Into selkies, yes,” the man affirms. “Or, variations of them. Creatures suited for life in water when their life on land has been taken from them in suffering. I’ve heard of legions becoming selkies in shipwrecks, but perhaps most well-known are stories of women who have been abused or abandoned, then taken in and reformed by the sea.”

That, Peter definitely needs more than a few seconds to digest. He remembers…standing over the water, calling out for help...fear, and his legs breaking from the fall.

Then: ‘ _Reformed by the sea_.’

He swallows thickly. “You-you said something about different powers?”

Thor nods. “Precisely. As I said, in some ways, selkies differ…beside appearances, one such difference is abilities. I imagine the range of possibility is endless, but one theory is that the power added is specific to what an individual values most. For example, some are gifted magical singing voices, others the power to manipulate currents and water itself...and still more, the ability to heal the injuries of others.”

Peter’s good hand clenches.

It’s at that moment that the door to the room swings open without warning, and Mr. Stark’s voice precedes his appearance: “Alright, kid, your old shirt’s in the wash and I got a couple of water-friendly choices here for you to pick from--” The genius stops in his tracks at the sight of the thunder god seated by the pool, and he frowns slightly as if the serious atmosphere is a bad smell in the room. In his arms is a small bundle of clothing, which he shifts under his arm as he takes in the other two.

“Point Break,” he starts slowly, casual surprise in his tone. “What the heck are you doin’ here, buddy? _How_ the heck are you here, honestly, does nobody tell me who’s invited to my own building anymore?”

Thor smirks. “Stark, it’s good to see you, my friend, and I thank you for your hospitality as always,” he says, raising his fingers in acknowledgement. “Banner invited me, as a matter of fact. He thought I might be of use in the recovery of young Peter here, seeing as there are things your science has yet to explain.”

“Did he now,” Mr. Stark says, with a narrow-eyed look that says he’ll be harassing Bruce later. “Thoughtful of him. I mean, you’re always welcome, but some forewarning is nice. So I can, you know, _over_ stock the kitchen and whatnot.”

Peter, still reeling from everything just revealed, doesn’t hold back his snort at the exchange. Mr. Stark looks at him, and then spots the bag of food.

“I see you got breakfast,” he says. “How’s the hand?”

“Erm, it’s- fine,” Peter says, flexing his arm a bit. It's still swollen a bit, but he won't complain. “A-and everything else seems to be holding up well, too.”

Mr. Stark hums, then proceeds to stroll over and drop his selection of shirts at the water’s edge. Peter edges along the pool wall to them and begins rifling through them, tuning out the conversation that the men get into as they catch up with one another.

It seems that all of the shirts are polyester or polyester-cotton combination, the kind that people wear to exercise. Smart, because they’ll hold up better in water. Some are bigger than others, all probably from Mr. Stark’s closet because it’s not like he had time to go shopping overnight. As he shuffles through them, Peter finds one that seems like it might be a better fit than the rest: a medium-size black shirt with some kind of band logo on the front. He holds it up.

“Nice taste,” Mr. Stark comments, noticing Peter’s choice. “That’s from my MIT days...yeesh, was I scrawny. It’s a wonder I haven't got rid of it yet.”

Peter brings it closer to himself. “You think it’ll fit?” he asks.

Both men appraise him, and suddenly Thor’s eyes fill with concern. “Peter,” he remarks, “you have quite a lot of battle scars, for one so young.”

Instantly Peter’s arms fold inward, the shirt falling against his torso like a shield.

“ _‘Ey_ ,” Mr. Stark hisses, elbowing Thor’s side. The action is completely harmless to the giant man, but he still looks at the billionaire confusedly, evidently not seeing the reason for the action. Peter’s eyes are fixed on the disquieted water in front of him, but he catches Mr. Stark making the universal gesture of a hand slicing across his throat.

“It’s fine,” Peter says quickly, looking up. “It’s- don’t worry about it, Mr. Stark, I know I- I have a lot of ‘battle scars’.” He forces a laugh.

Mr. Stark still looks at him unsurely, but Thor smiles. “It’s not a matter of shame to have scars,” he says kindly. “On the contrary, it is a sign of survival. Of prowess.”

Peter bobs his head, eyes falling back to the shirt. Wordlessly he slips his arms in and pulls it on, then strokes backwards to get a feel of it in the water.

It’s a perfect fit. That stirs something for some reason.

Mr. Stark claps his hands together. “Well, that’s one problem solved,” he says, rolling on the balls of his feet. “Whaddaya say we get your fish butt to the med bay for another check-up, eh? I’m sure Brucie Bear is eager t-”

“Nonsense!” Thor interrupts. “The selkie child needs entertainment!” He holds out a hand out and curiously, Peter comes forward. He has no warning though when the god suddenly reaches down and _lifts Peter into his arms_ , water splashing as Thor stands and cradles him as easy as a child lifting a teddy bear, apparently not minding his clothes getting wet.

“Uh, what- Thor-” Mr. Stark startles. “Thor, put the merkid down.”

“The best way to ensure proper healing is to keep spirits up,” Thor insists, and Peter yelps and grabs hold around the man’s neck as he’s slung into a piggy-back carry, tail lifted to the side by one of the man’s tree-trunk arms. It’s not a very secure hold, but with the sticky pads of his good hand holding tight to Thor’s shirt, Peter doesn’t feel like he’ll fall. He does kind of feel like he just got a shot of adrenaline, though.

Mr. Stark holds his hands out worriedly. “Okay, okay, just- be careful with him, alright? Pete, you good?” The man looks at him like, _Just say the word and I’ll tame King Kong here_.

And Peter looks _down_ at him, that’s how high up he is, and it feels kind of exhilarating. As unexpected as it got kicked off, now that Thor’s suggestion sinks in... Exploring the tower? That honestly sounds _awesome_ (and not just because it gets his mind off of heavy things, though that’s an element).

Peter smiles.

“I’m good.”

 

…

 

Tony tells them he’ll catch up.

 

He goes to the lab.

 

Seated in a desk chair by the holo-table, he spins himself in slow circles for a bit, arms crossed and eyes on the ceiling. After a few minutes, he puts his feet down and asks, “FRIDAY?”

“Yes, Boss?”

Unlike Peter, Tony has the ability to lie...to pretend he wasn't eavesdropping.

“...Run a facial recognition search matching the boy upstairs...and focus on kids who went missing in the years before Star Wars: The Force Awakens came out.”

“Right away, Boss.”

Information fills the screen.

…

…

…


	3. beneath the surface

**Summary for the Chapter:**

> So the time starts to pass like that: a companionable game of hot potato with Peter The Merkid, as the present members of the team keep him company during his stay at Avengers Tower.

**Notes for the Chapter:**

> Guys guys @vanillabean_97 made fanart of mer!Peter and Thor and it's the cutest thing you'll see today so please check it out along with all their amazing art: [art link](https://twitter.com/vanillabean_97/status/1125306705380691969?s=21)
> 
> uh also...time slipped out from under me and i have lots of reasons for that but mostly i'm just sorry for leaving y'all hanging despite all the lovely enthusiasm. thank you for waiting! im back now!! let's do this crap!!!

…

…

…

That first full day, Tony can’t help but think that Peter looks a lot like a baby cartoon animal - the kind that Disney princesses have as cutesie sidekicks riding around on their shoulders, there to appeal to the little kids in the audience so their parents will buy them the plushie version from movie merchandise and then it gets cuddled with day and night and kids cry when they have to leave the house without it because it’s _that_ cute.

In this case, Thor is the Disney princess (go figure) and Peter is the bright-eyed baby bird or chipmunk or whatever; he hangs on Thor’s every word, but is also enthralled with the entirety of his impromptu tour, emotions reading out on his face like an open book. There’s a lot to see, yeah, not just because they start on the 68th floor with its stunning aerial view of Manhattan, but also the living spaces and training rooms and all other appendages worked in to the Avengers’ personal floors are top of the line, because Tony Stark doesn't design crap and certainly not for his teammates.

Their little adventure lasts a few hours and only stops because Bruce finds them. He’s even more flustered about Peter riding around than Tony was, insisting that it’s close to noon and his patient needs food and rest and _for heaven’s sake, man, not everyone is practically immortal like you_ , please _set him down-_

Peter smiles. Peter laughs.

Tony watches him, and it’s like looking at a double image, shifting back and forth in his sight like an optometrist testing lenses. There’s the 15-year-old merperson version, real and present...and then there’s the other version, the one who lit up his holoscreen earlier that day in school photographs from a missing kid’s case file.

His face was the same. Definitely different in some ways, like being younger by a few years (age 13 at the time of disappearance, according to the report) and it showed in the way he hadn’t yet grown into his big ears, and even less grown into his still-too-big eyes, then framed by round Harry-Potter-style glasses. And oh, yeah- there were _legs_ on him then. But the hair, the eyes, the smile...it’s either the same kid or a it’s a doppelganger.

Merboy, Fish-butt, Peter…he now has a real name: Peter Benjamin Parker.

(And even knowing the facts, Tony Stark - for once - isn’t sure what to do about them.)

“-ony? Did you hear what I said?”

Tony snaps back to the here and now. He’s leaning on the kitchen counter, the others nearby in the lounge area with some food that Thor helped them to (again, though this time the meal choices were supervised by Bruce), and Peter is spread across a towel on the loveseat in all his fishy glory. As Tony watches, the kid looks up from a bowl of food and their gazes meet.  

Tony breaks contact first. “Hm?” he hums, looking at Bruce who is looking at him.

The scientist has a couple glasses of juice balanced in his hold, about to take them over to the coffee table. “I said, Natasha and Clint said they’ll be back later this week after a visit to Clint’s. They got the paperwork for the whole ‘sea monster’ thing taken care of.”

Tony nods distractedly. “Right. Case closed.”

“Join us, Stark!” Thor calls, benevolently waving a fork with a ravioli on the end. “The selkie child has a good many questions about your building which I told him you could answer better than I.”

Peter sits up a bit straighter, glancing back at Thor. “Wha- uh, I mean it’s fine, really, you don’t have to—" he starts.

But Tony is already gravitating towards them. Thor gets up and wanders over to the counter with his dishes, starting up a cheerful conversation with Bruce as he goes, and Peter looks after him before pressing his mouth shut and looking to Tony. Tony himself takes a seat on the arm of the adjacent couch, folding his arms and raising an eyebrow.

“What’s up, kid?”

Peter’s tail folds in closer to him. His pelvic fins twitch. “I just- I was curious about the arc reactor. Is it- is the one that powers the building the same as the one that…?” he taps his chest, looking at Tony’s shirt.

( _All A’s, enrolled in several STEM classes, described by his teachers as a very bright student…_ )

“The one that powered me?” Tony says, rapping his knuckles against his sternum, where now there are only scars to carry the memory of a foreign metal implant. It’s something else Peter Parker would be behind on, having missed a couple years of watching the news: “I got it taken out a year ago, shrapnel and all. But yes, it was the same device, only smaller and using a different core because it turns out palladium poisoning does not a healthy man make.”

Peter blinks, looking, if Tony is correct, vaguely disappointed. Nevertheless he nods. “Oh. That’s good that, uh, it’s not hurting you anymore. Because it probably didn’t, uh, feel…great. I just think it was really cool, how you- you used it to be a hero.”

Tony leans across the coffee table and pours himself a drink of juice. “Iron man is less cool when he’s not part iron, right?” he muses, eyes on the reflection in the glass.

He smirks into his drink when the kid begins sputtering in a high-pitched voice, “I-I didn’t mean to say that you’re less of a hero without it, Mr. Stark! Of course not that! You’re- I really admire what you can do, you’re, like, the coolest _because_ you don’t have any special powers or training and like- oh gosh, this is not coming out right—”

“Relax,” Tony says, before he’s even fully swallowed a mouthful. Peter’s mouth clicks shut and the man can’t help but think that the rambling thing is actually pretty endearing, if painful in a secondhand way. Without invitation, a thought pops into his head that _the kid is probably used to rambling to himself_. Tony cringes internally.

He lets the kid see that he’s unvexed as he replies, “I know what you mean, kid, I’m not offended. Tell you the truth, it was a hard decision on my part to get the thing removed. It saved my life, right? Instigated my origin story?”

He clears his throat a bit, hating, as he always does, making any allusion to his own feelings. But those slightly-reflective brown eyes are locked on him, and he feels obligated to finish for whatever reason. “Well, it served its purpose. Now I have other things—” he gestures vaguely, “ _—people,_  giving me purpose and whatnot...And of course I can still put on an arc reactor when I need it, shrapnel not included.”

Peter nods slowly. “Shrapnel not included is probably for the best,” he agrees. Tony sees him tapping restlessly at the edge of his bowl with those sticky pads of his, expression unreadable.

 _Something saved your life, too, if Thor is right_ , Tony thinks, watching the kid intently, as though he can will him to bring it up first. _It saved your life but you’re all by yourself because of it._

The kid looks up hesitantly. “Mr. Stark?”

Tony hums, bracing himself.

“...D-do you guys have any Pop-tarts?”

And, Tony supposes, this is a teenager after all. He can’t help but drop his face in his hand as Peter hurriedly spouts off, “I mean- I just thought, because you mentioned yesterday- Mr. Stark, I’m sorry, I don’t know why I—” and keeps his head there when Thor starts shouting from the kitchen, “Did you say Pop-tarts? Do you have Pop-tarts around here, Stark? I hope they’re of the strawberry variety!”  

“Help yourself, big guy,” Tony tells him long-sufferingly, and as Thor goes about doing so, he sighs to Peter, “Okay, did you have any other questions about my _building_?”

“Uh. Uh.” Peter glances around the room in a searching way and it comes to Tony, belatedly, that the Pop-tart thing was probably a diversion of sorts. Huh.

“Oh, yeah, I remember something I did want to know!” the kid announces, straightening up. “Who all lives in the tower? Of the Avengers, I mean.”

“Fair question,” Tony acknowledges. “And to tell you the truth, it changes every day. Nat and Steve each have their own apartments somewhere, Clint has his family’s farm, and Thor has... space... but depending on the level of chaos in the atmosphere or alternatively, the amount of free food in my cupboards, everyone does have their own floor here when there are missions and things. I don’t really keep tabs anymore. I know for sure is that Bruce is here, but it’s not like we’re a big happy family or anything; I’m primarily running the business or building crap or with Pepper.”

The scarlet tips of Peter’s caudal fin flick. “I’m sorry… Pepper? Is that, is she-”

“Pepper Potts, my fiancé. Former CEO of Stark Industries." 

Curiously and cautiously: "Former?”

The noise of Bruce and Thor gets fainter as they leave the room headed who-knows-where, possibly to lend privacy and/or to ransack other areas of the tower.

“She’s been...chronically ill...for a while now,” Tony sighs, rubbing the back of his neck. He taps his chest again. “Same fiasco that led to me taking out the shrapnel? Yeah, it’s a long story but long story short, a freak with a complex against me was injecting people with something called Extremis, basically turning them into human bombs. Said guy got Pep and… well, she survived the injections but when I managed to reverse the effects, it wasn’t too long before we noticed side effects. Mostly it’s just fatigue and body aches, but it’s been getting so bad that she can hardly get out of bed some days.”

Peter’s eyes fall to his lap. “That sucks.”

Tony snorts. “Well said. But on a side note, if you ever need to woo a lady, a necklace made from the metal bits in your heart makes a great proposal gift.”

“I’ll keep that in mind.”

“Eh, hopefully you won’t need to. Alternatively, you do have a lot of access to sea shells. Or little starfish. Or magical fishbutt scales.”

The kid grimaces playfully. “I feel like that last one would be like giving someone my toenails, Mr. Stark.”

“Hey you never know, your special someone might be into that.”

“If they can get over the tail in the first place, you mean.” It’s said in good humor, but Tony sees the shifting, a self-conscious hand smoothing down the fins at his hip.

Taking another swig of juice, Tony pulls to his feet. He claps his hands together and looks around. “Let’s find something to do other than talk about our feelings, shall we? I’d like to delay the inevitable vulnerability hangover as long as possible. Seems our associates have abandoned us so we’re on our own. How’s the tail, need watering?”

“I think I’d be good for another couple hours. But like...Mr. Stark, you don’t need to babysit me or anything, I can go back to the pool and I’ll be fine. Like I know you probably have things to do—”

Peter's interrupted with a scoff. “‘Things to do’,” Tony repeats. “You say that like I’m responsible or something. First things first, I’m gonna get you your dang Pop-tart—” he smirks when the kid’s cheeks redden at that, head ducking, then gestures to the wheelchair, “—and then you’re getting back in your mer-mobile because I know for sure that Thor didn’t show you the one place here that makes the rest of the tower look subpar: Tony Stark’s personal workshop.”

The kid's curly-haired head shoots up. “Your- your lab?” he squeaks, eyes wide.

And yes, there it is: the emergence of the science nerd Tony expects Peter Parker to be based on his background information.

Tony Stark grins.

…

So the time starts to pass like that: a companionable game of hot potato with Peter The Merkid, as the present members of the team keep him company during his stay at Avengers Tower.

When Tony’s in charge, he works the cover story regarding Peter as an internship recipient and by the second or third occasion of showing him around his stuff, he finds that the excuse is actually pretty passable if anyone wanted to test it by watching them in the lab.

The moment the kid says _woah is that a mass spectrometer?_ (it is), Tony realizes that the wonder and enthusiasm rolling off him like waves goes beyond that of the typical visitor to his lab - and there are no typical visitors, because Tony rarely lets strangers in, but if he did, if he pulled someone off the street and showed them around, he’d expect them to be in awe because _look at all the shiny science stuff that makes the Avengers’ gadgets!_ Not Peter; well, yes Peter. But yes in a different way because the kid really seems to understand or at least _crave_ understanding about what he sees, and Tony, watching, finds this completely unfair. Just completely, because how is he supposed to see that look on his face- like a child who’s spent their entire life coloring with Crayola markers and just now discovered the materials found in a professional painting studio- how can he see that and _not_ want to indulge it with every explanation, every hands-on show-and-telling of things, every opportunity to feed the fire in his eyes?

It’s impossible is what it is. None of his teammates, not even Bruce because he is already seasoned with experience and well past the awe he had when he first moved in, and certainly no one so young and impressionable as Peter has showed this much bright interest in what Tony himself loves before.  

Equally as pleasing is introducing Peter to the sequels of the Star Wars movies he’s so famously in love with. They make it an Event, with popcorn and soda and excessive amounts of pillows for the merboy to lounge across on the floor like a little kid. Thor even joins in for one of the films, though Tony gets increasingly annoyed by the number of times they have to pause and answer his questions about what’s going on. Peter doesn’t seem to mind- he trips over a spray of words in his vigor to share what seems to Tony to be way-too-in-depth analyzations given to fictional space people.

When they finish their marathon, the credits rolling, Tony asks, “So? Was it everything your fish-butt heart desired?”

Peter, sprawled on his back, staring at the ceiling with a far-off look, takes a moment to compose an answer.

“As someone who is more invested in the original trilogy as opposed to the slightly more political prequels,” he answers slowly, “I think I’d say the sequels were enjoyable overall, but also I recognize that they don't stand up to the craftsmanship and storytelling of the originals.”

There’s a beat of silence. Thor, laid on the floor aside Peter like a pair of girls having a slumber party, says, “The heroine Rey… she is what Barton’s son would call a ‘boss’, I think.”

The merkid jackknifes up in a flurry of enthusiastic agreement and the two dissolve into a serious discussion of their favorite parts. Tony just rolls his eyes.

When he goes to spend time with Pepper or forces himself to attend to SI things, Bruce is always willing to oblige to letting Peter trail him in his day. Mostly that means letting the kid sit in on his research, but he also checks up on Peter’s injuries and makes him nutritional meals and chats with him about his publications. Tony, surprised, even catches them having a conversation about the mechanics of the Other Guy in Bruce’s body- a typically sensitive subject- and Peter telling him right back about his own underwater-suited biology. Overall it seems like Peter takes to Bruce and Bruce takes to Peter with the like-minded agreeableness of a pair of cohesive water molecules.

Thor’s turns are more...chaotic. When Tony finds them together, the god’s either regaling his captive audience with personal battle stories or those of the Avengers or of Asgardian mythological figures (stories that sometimes involve carrying Peter around on his shoulders again for a more vivid reenactment of adventure scenes); or they get into other random, Thor-like activities. Once they make ice cream sundaes out of everything but the kitchen sink; another time Thor teaches Peter with painstaking care and detail how to play “a traditional Midgardian game called ‘go-fish’”, and Peter is fully attentive with impressive stoicism as he nods along.

Tony drew the line at the time he caught Peter sticking to the gym ceiling by one hand, tail flailing, Thor laughing hysterically below him. It’s like a scene from an alcohol-induced hallucination.

“I told him I could stick to things and he wanted to see how much,” Peter explains, half repentant but half containing laughter of his own, when he catches sight of Tony staring from the doorway. “So we...got carried away, but now he won’t stop laughing long enough to get me down.”

“He looks like a lindworm hanging there!” Thor hiccups, actually freaking hiccups, leaning against some equipment behind him like he can’t stay upright. “Odin, that is magnificent!”

“What’s a lindworm?” Peter asks Tony as the man wrangles him down, arms encircling his middle where scales meet flesh and legs staggering only slightly when Peter lets go of his hold on the ceiling.

“Your guess is as good as mine.”

Cultural differences aside, Peter is kind of in love with Thor.

In between the nonsense and sense alike, they cart the fish boy to his pool for swims when he’s been out of water too long, and slowly his stitches and bandages come off as he heals with a speed that’s probably supernatural but not quite Steve Rogers level.

 

...And all the while Tony waits and waits for Peter to bring up his origin as a human. As someone who is not generally a patient person, the knowledge feels like it’s burning a hole in his pocket.

 

“This is nano tech,” he tells Peter one day when they’re in the lab together, pulling up a giant magnification of one tiny bot on the holoscreen for Peter to see. “Microscopic AIs connected on a shared network, controlled by the user via neurological interface. I’ve been studying these buggers for years. Trying to see if I can reverse engineer something like what the Wakandan tech princess has- though I don’t have access to vibranium, so I make do with what I got.”

The holoscreen display changes to accompany his words. “So far I’ve found a way to get them to work together but I’m still figuring out how to get them efficient for on-the-go use. They require an insane amount of energy, so-”

“-It's impractical to carry them around, when they'd need to be hooked up every five minutes?” Peter guesses, his eyes reflecting blue from the screen as they flick across it. Doesn't even look sorry for interrupting. Tony is impressed.

“...Yep,” the mechanic says, popping the P. “Anyway, wanna see the prototype? Of course you do.” He turns without acknowledging a small snort from Peter.

Within a minute he’s got the neurotransmitting headset on and a containment unit of nanobots on the table between them. Taking a seat, Tony concentrates and wills them to snake out, off the table and into the formation of a Mark 46, a suit he could build in his sleep. Without even looking over, he can tell Peter’s eyes are wide and his mouth forms a perfect “O” as he pillows his chin on his arms in awe, watching the bots assemble.

“Could you wear clothes made of these?” he asks when the suit is complete.

“I mean, only if you had a portable way to charge ‘em, like I said.”

“Could you charge them with an arc reactor?”

Tony blinks. “Uh. Maybe.”

“If you had an arc reactor you could take on and off,” the kid goes on, “the bots could charge whenever you’re not using them.”

“That containment unit would be kinda heavy. Dense.” 

"Are there lighter materials you could use?"

Tony tilts his head back, calculations and hypotheticals already whirring in his head. Before he can come to anything to say, the kid's train of thought alights on a new path:

"Can I try using the headset?”

Putting a pin in his thoughts, Tony blinks to process this. When he does, his eyes narrow. Peter offers a shy grin.

“...Fine,” he concedes, eliciting a soft cheer from the kid.

The nano-built suit is still standing when Tony hands over the headset. Peter leans out of his wheelchair to retrieve it with hands reverent enough for a crown of jewels and then, after a couple pointers from Tony, he gets it into position on his own head. 

“Woah,” he breathes, even though he hasn’t done anything yet. “So I, what, think heavy thoughts and they'll obey?”

Tony shrugs. “Essentially.” He leaves out the part that it definitely takes some practice to work the headset coherently; it’s rather like playing pictionary inside your head where your mind is the artist and the bots are the guessers.

Staring hard at the Iron Man suit, Peter tilts his head as though deciding what to do with it. One of his fingers twitches on the table and a second later the suit’s legs shudder and shuffle. It lifts one leg and then walks forward, pulling out a chair and taking a seat with them like a sentient being. The movements are painstakingly halting and awkward but they happen eventually and Peter looks pleased. Tony thinks that's it, but then the bots making up the legs begin to disassemble from their mould and change shape altogether. 

Gradually, the legs rearrange and merge into one long, inelegant thing. A pattern of sharp little chinks form across the length of it and the bottom end flattens and spreads and forks. Then Tony gets it: Peter's made a mediocre version of a robotic fish tail.

“Behold,” the merkid says. “Iron- _Mer-_ n.”

Later the same afternoon, Tony skeptically goes about mathematically simulating the idea of an arc reactor containment unit whilst the kid gets free reign with some old blueprints. It keeps them both busy and quietly caught up in their own thoughts. FRIDAY obliges to throw on some background music (80s hits, a genre they both agree on) and the only other sounds for awhile are Tony muttering to himself and Peter occasionally asking for certain tools.

Though when Peter does let out a huff of frustration some unknown amount of time later, Tony realizes maybe they’ve been there long enough that the merchild needs feeding again. Here is something he's learned about Peter: the kid's a bottomless pit for food of all kinds. 

While Tony's paused and eyeing him, Peter glances up and misinterprets the look he’s getting. “Sorry, not trying to be annoying,” he hurries to say. “I just- I can’t figure out this bit...”

“Lemme see,” Tony offers, scooting over in his rolling chair so he’s by the kid’s shoulder.

It hits him somewhere in the middle of explaining and seeing Peter’s mental lightbulb go on how very mentor-mentee this feel is, this vibe that's taken up residence in the space between them. It feels...right.

Then Tony turns to look at the kid sideways, and his eyes catch on the close-up sight of the inhuman slits of skin on the side of Peter's neck. The man's hand, reaching over to guide Peter’s on something, jerks on accident. He pulls it back and coughs quickly to hide the moment, face burning.

(He’d forgotten, for a minute there.)

Luckily Peter’s distracted enough that the slip goes unnoticed, as he says in an almost wistful way, “You know, Mr. Stark, robotics is awesome but chemistry is more my thing. _Was_ more my thing, I guess…” His eyes raise to the ceiling a bit like he’s seeing something that Tony’s not. Something long past.

( _Peter Benjamin Parker_.)

Peter glances at him, then at his fingers. “You… you’ve probably noticed that I’m not…telling you everything. ‘Bout me. Right?”

This is it.

Tony stays still, feeling like if he moves he'll scare Peter like a baby bird or chipmunk or whatever he imagined him to be a few days ago. His blood charges a bit faster in his veins in hopeful anticipation. Saying nothing, Tony waits, watches, pours ' _trust me, kid'_ into his gaze...

A deep breath. “I was actually—”

“What, no one called us to this party?”

Both man and teen jump slightly in their seats and turn sharply as the door to the lab swooshes open revealing two familiar (but, frustratingly enough, unwelcome in this particular moment) faces. Clint, the one who called out, is strolling in and followed close behind by Natasha, both dressed in casual clothing and both taking in the sight of Tony and Peter side-by-side with different degrees of curiosity.

“I know for a fact you do not party,” Tony states dryly, eliciting a scoffed snicker from Nat. “Seriously, since when do you two invite yourselves into my lab? FRIDAY, what is this intrusion?”

While the AI sasses back some nonsense about all-access codes, Tony sees the kid flush quietly and there it goes: the important moment slipping away before it got to happen. Tony mentally bangs his head into the wall.

“You’ve been hogging the mermaid,” Clint accuses obliviously, folding his arms and meandering around the table where they sit. “When are the rest of us supposed to ogle him and/or talk plans for our kids’ birthday parties?”

“Birthday parties?” Peter repeats in interest, at the same time Tony says, “I think the frick not.”

“We got dinner upstairs,” Nat interjects. “Just waiting on you two.”

“I think I- I need to stop by the pool first,” Peter admits, a familiar look of discomfort on his face as he sweeps aside the blanket covering his tail and scratches at the scales on his side while Clint and Nat, less used to the sight of the fish half than Tony, Bruce and Thor have become, stare in a way that’s probably unbecoming for the likes of super spies. Tony sighs.

“Alright, we’ll get Pete watered and bring him by the common area kitchen, as I assume that’s where you’re at. I actually have dinner plans with Pep after her doctor appointment tonight so I’ll catch up later.”

Peter looks up at him as he stands and starts directing his chair to the elevator, a look of mild alarm on his face. Without his saying anything, Tony can practically hear the nervous stuttering of ‘ _Y-you’re leaving me alone with all of the Avengers at once?_ ’

“Capscicle is still out galavanting on his solo mission, right?” Tony asks the others.

Natasha nods. Clint says with dramatic snobbery, “Just us. The most important characters. And Thor apparently, who nobody told us was coming, by the way."

Tony _pfft'_ s. “Welcome to the club.” Then, to Peter, as they get in the elevator and the others follow, evidently coming to the pool too (to see the “mermaid” swim, Tony’d guess): “Well, that’s just…four out of six Avengers. You’ll be fine, kid.”

Peter gulps.

…

…

…

The sun is due to crest the eastward horizon in about an hour when Kraven approaches the obnoxiously tall tower with its beaconing letter A.

“ _The creature we seek has the appearance of a boy, this is true_ ,” Calypso had said, having consulted her cards. “ _But the magic in him...it felt like that of a_ sirène _._ ”

Kraven had been otherwise distracted in their encounter with the Iron Man’s vehicle and so barely noticed the child hiding in the back. Hiding, or was hidden, Kraven isn’t sure and doesn’t care, because whether they caught it willingly or not is not his concern. His concern is the eagerness in Calypso’s eyes.

In spite of his bulk, he is light-footed, and rather than his normal animal-skin attire, he is clothed darkly to avoid detection. A skyscraper is admittedly unconventional compared to his usual milieu, but all the same he found out what he needed to to get in. If all goes well, he will get what he came for without the sleeping inhabitants being the wiser.

He smiles and advances.

…

It’s probably around five in the morning, but Peter is awake. He floats on his back in his pool, tail paddling lazily from side to side to keep up a gentle propulsion across the water’s surface, good arm floating at his side, bad arm resting on his stomach. The water buoying him and lapping at his sides feels just like a hammock rocking, and that along with the soothing sound of flowing water in his ears _should_ be a perfect combination for sleep.

Instead, the restless excitement vibrating under his skin makes him feel like a container of energy. He got a few hours of rest but the excitement woke him, filled his head with disbelieving memories of the previous days and bright anticipation of what comes next.

Is this what it’s like to be around people? He’s practically forgotten.

...Or it could just be the fact that he was given pizza by, listened to stories told of, and then rewatched the classic Star Wars films with: Black Widow, Hawkeye, Thor and Bruce Banner. If that’s his waking reality now, he’s fine never dreaming again.

The fins at his hips slap the water twice in delight.

 

He is humming to himself when a sudden noise somewhere interrupts his musings. 

 

The walls of the large room are lit only dimly by the reflection of stirring water patterns, the night beyond the windows clear and cloudless. As Peter listens, he thinks he might’ve imagined it because there are no other sounds out of the ordinary for a long pause, but then he hears again:

A muffled thump somewhere on this side of the building…from the outside. Like something coming in.

He sits up fully and swims to the cement edge nearest the door. “Hello?” he calls softly, thinking maybe it’s just an Avenger up early…they are an eccentric bunch, after all.

No one answers.

But when he concentrates he does hear what normal ears might not: purposefully quieted footsteps, somewhere in the building.

He’s not sure why he does it, but the action feels right when he considers his only other option is to sit here and wait in restlessness and mystery: his good arm gripping the rail and his tail working for upward motion, Peter pulls himself onto the ledge of the pool by where his chair is parked. It takes a few minutes of effort and awkward wrestling with his body, but with the brakes set on so it can’t roll anywhere, Peter manages to maneuver himself up and into the seat, panting slightly and slippery with pool water. Once he makes it though, he huffs triumphantly and smiles to himself before setting his hands to the wheel rims and guiding them backwards, then steering for the door.

…

The interior of the building is as sleek as the exterior, with high ceilings and minimalistic design. He learned that a certain set of floors are privately kept by these “Avengers” (who seem to be highly extolled warriors, but everyone has their weaknesses), and it’s the floor of the man from the car that he expects to find his prey. A concrete stairwell connecting the entire building - probably rarely used, considering the sheer number of floors - leads him there. Upon stepping out, the hunter narrows his eyes calculatingly, sniffs the air once, and stalks decidedly down one hallway.

For about twenty minutes he searches, familiarizing himself with the layout and utilizing his tracking skills to infer as much information as possible. In the west wing a grand living quarters houses the beating of two hearts, both sleeping adults. Ignoring these, he finds a common area and a gym and a medical facility and various other utilities and-

He stops.

 

A heartbeat. Faster…younger…awake. And close.

 

Silent as ever, the hunter rounds on the sound and sees what might be a closet: one quiet, nondescript door in a building where all other doors and entrances are grand and welcoming. His turned and directed senses now pick up a faint trail of water on the ground, the smell of stress hormones that cornered animals give off, the sound of quick breaths stifled into a palm. The young pulse quickens as he draws near.

Kraven smiles.

So focused is he on the familiar euphoria of being in his element, of stretching out his hand to the door knob to reveal his soon-to-be-prize, of wondering what fight it might put up and how victory will feel when Calypso smiles at him and his collection of trophies grows—

—he does not notice the newcomer until they are upon him.

…

Peter’s jammed-shut eyes— _if I don’t see the scary-looking stranger, the scary-looking stranger won’t see me_ — snap open at the sound of a heavy thud outside the little room he’d locked himself in when he realized the person wandering Tony’s floor was _not_ Tony or any of the Avengers. He barely has time to wonder what happened before a blessed voice speaks up.

“Nice necklace,” the Black Widow says, casual and blunt as always. “Did you pick it out at Claire’s?”

There’s a deep breathless-sounding growl, as though the giant man Peter saw lurking before is pinned beneath her and is somewhat upset about it. A flash of awe dilutes some of Peter’s hand-tingling fear from moments before, because he mentally compares the height of Nat to that of the guy and has to resist the urge to peek open the door and see for himself how she is keeping him down.

“This _amulet_ …” the man hisses lowly, before sounds of a scuffle interrupt, two forces clearly clashing for dominance. Ultimately one escapes the hold of the other so that they’re facing one another in a hostile stand-off, and only then does he finish: “...is no ordinary trinket. It grants me the enhancements of a _jungle cat_.”

He can imagine Natasha cocking her head, cool and confident. “That was kind of defensive. Nothing wrong with a man who likes jewelry, but at least own up to it. Your masculinity’s looking a little fragile from where I’m standing.”

“ _Romanova_ ,” the man says, causing her circling footsteps to still. He chuckles lowly. “Oh, yes, I have heard of you. Kraven does his research.”

“And who does Kraven do his research for,” Natasha asks after a beat, carefully calm.

“For himself,” the man snarls, and with that, he must throw himself at the spy because the sounds of fighting ensue.   

Peter’s hands grip the arm rests of his chair. His tail scoots the wheelchair a little further into the mounds of cleaning supplies around him. There’s a fight going on mere feet away. An _Avenger_ fight. He wishes he had literally any idea how to respond in this situation but what could _he_ do? He reaches one hand tentatively for the door knob but snatches it back a second later when the door rocks with a weight being slammed against the other side.

“Down, kitty,” he hears Natasha mutter.

Her weight dodges away a second before the sharp tip of a knife pierces through wood less than a foot from Peter’s face. A snarl from jungle-cat-man. The weapon leaves a ragged hole when it is yanked back out and a stream of light pours in. Peter's pulse sounds like storming waves in his ears, jolting up a notch with each development and then, as one yellow eye peers through, zeroing in on him instantly, he feels his heart give an unhealthy flop. 

 _Should’ve stayed in the pool_ , he thinks.

“Hello there,” Kraven purrs. Peter can’t see the rest of his face but he can picture the smile that goes with that greeting, full of too-sharp teeth. A hungry shark.

The door handle starts turning. 

The door handle stop turning.

Peter is frozen, staring through the now-vacated peephole where he sees Kraven stumbling back with Black Widow on his shoulders. His neck is gripped in her thighs.

The man grunts and attempts to buck her off but she clings like this is a move she's done many times before. Kraven's face grows redder and redder and Peter has a passing thought that Black Widow could own any rodeo she wanted, because she gets hit into the opposite wall and she still won’t let go.

Kraven's arm flails back to claw at her and- and only then does she grunt and loosen her grip enough to be flung off. She lands on her feet but falls to one knee in a defensive crouch immediately, expression taut. One hand grips her left shoulder tightly.

Her narrowed eyes glance past him and Peter and Kraven both hear it (too late, in Kraven’s case) a second before a sparking arrow slices the air.

The big man’s spine arches the instant he’s hit, electricity crackles in thin veins over his body, and then he collapses twitching on the floor.

“Took you long enough,” Natasha pants drily.

Clint Barton toes Kraven’s fallen form with one socked foot, and Peter registers for the first time that Nat is in a tank top and sweats and Clint is similarly dressed down besides his bow- both of them probably, like Peter, drawn to the sound of the intruder without knowing what to expect.

“Hey, hey-” the archer’s alarmed voice is in contrast to everything Peter’s heard out of his mouth in their interactions so far. He drops to his knees by Natasha’s side, his hands bracing her as she slumps into him. He grips a hand over her clenched ones and that’s when Peter sees: Natasha’s fingers are coated in blood.

Kraven’s knife is lodged below her collar bone.

“It’s fine,” she says. To the contrary, her face is paling steadily.

The lights in the hallway suddenly raise, covering all but the kid in the closet in bright illumination. Peter blinks at the hole as his vision readjusts, but he hears brisk footsteps round on the scene and Mr. Stark’s voice abruptly assessing things with a curt and bewildered, “Why is Tarzan passed out on my floor?”

Hawkeye says, “Nat needs medical.”

“Medical is asleep. It’s butt-crack-of-dawn-o’clock,” Mr. Stark says, but he must see the injury because his tone changes in a flattening of emotion: “Friday, Nat needs medical.”

“I have alerted Dr. Banner as well as the on-call medical staff,” Friday reports from above, her Irish-accented voice urgent. “However, Boss, the wall sensors suggest that Miss Romanoff’s brachial artery may have been hit and if this is the case, she will need medical attention sooner than the estimated arrival.”

Clint curses. He’s eased Natasha onto her side on the floor, her injured shoulder elevated, her face pinched. She watches his face, breaths shallow.

 

And Peter doesn’t have to think.

 

He twists the closet door handle and pushes himself forward, adding momentum to the door as it bursts open. Mr. Stark whirls, clutching his heart. “Kid? How are you- why are you in the closet?”

Instead of answering Peter very clumsily throws himself off the wheelchair, to Mr. Stark’s vocalized distress. It sends the chair skidding backwards and Peter falling forwards and onto the floor beside Clint and Natasha. They glance at him: Clint still too distracted by Natasha to react, Natasha expressionless and probably knowing where Peter was all along.

As Mr. Stark retrieves the chair, still muttering, Peter adjusts himself onto his forearms. He's shaking in anticipation but manages to right himself, tail tucked under him like someone who had knees might kneel.

“Let me...” he says, trailing off as he isn’t sure how to explain other than to just do it.

 

There’s no going back from this; this is full disclosure.

 

Peter lifts his hands tentatively, a gesture that looks like he’s calming someone down (maybe it’s him). Natasha’s eyes find his.

“Let me?” he says again, this time a request. She can’t possibly know what he’s asking but she nods anyway. He takes a deep breath and his hovering hands ease forward.

“Kid,” Clint says lowly, and it sounds like he means to say ‘what’s going on’ and ‘what are you doing’ and even a tiny bit of ‘can you help her?’

 _Yes_ , Peter thinks to the last question, and carefully hopefully fearfully reaches for Natasha’s shoulder at the same time he reaches for the place within himself he knows as the not-human part.  

…

Tony watches in total confusion from behind as Peter places his hands gently over Natasha’s wound. Blood is seeping down her arm and chest in a macabre display despite how tightly Clint is gripping around the knife to keep it stable.

“When I say ‘now’, remove the knife,” the merboy says, his tone one of… what exactly? He sounds suddenly older than sixteen.

Clint doesn’t object which surprises Tony because he himself is opening his mouth to say that removing the knife will cause her to bleed out faster, but the wind is stolen from his sails quite efficiently when Peter’s hands start to emanate a faint _glow_. It’s bluish in color, the same as Tony’s seen in photos of the sea when lit by glowing algae.

Tony's feet move of their own accord, sidestepping to the other side of Nat so he can see Peter from the front. The kid’s eyes are closed but his face looks ethereal in its calmness. It’s almost like the skin of his sticky-pad fingers have a previously inactive form of bioluminescence hidden in their cells, except this glow- almost unnoticeable in the light of the fluorescents overhead- spreads with all the fluidity of water filling a glass into the mangled wound on Natasha’s body, and Tony’s pretty sure that isn’t how bioluminescence works. Not in natural, knowable, of-this-world science, anyway.

Natasha exhales softly. At the same time, Peter winces.

Beneath his fingers, something is happening.

 

_“In some ways, selkies differ…beside appearances, one such difference is abilities. One theory is that the power added is specific to what an individual values most. For example, some are gifted…the ability to heal the injuries of others.”_

_“I just think- well, I think that if I have the opportunity to help and I do nothing then, whatever bad thing happens is on me, right?”_

 

“Now,” Peter gasps.

Clint’s really trusting the kid this time. He is mercifully swift, unsheathing a jagged blade that Tony would call a _dagger_ the instant he sees it in full, and both Natasha and Peter give simultaneous cries of pain. A second later, the former begins to slacken in relief and the latter grips his shoulder and grits his teeth, eyes cracking open. He blinks at what remains under his other hand then withdraws and slouches into himself.

The glow is gone.

Clint immediately takes Peter’s place, muttering to Natasha, checking her over, cursing in a jumble of thoughts that flit from one emotion to the other, Clint-style, but Tony only stares at the kid. Peter, Peter Benjamin Parker, who is gripping his shoulder with both hands now.

When Clint ruffles the kid’s hair suddenly in a burst of praise and affection, Peter cracks a smile up at him and he shifts and Tony sees that beneath his hands there is a darker stain than the hand-me-down shirt’s black fabric should have.

Peter sees Tony looking. He doesn’t say anything as Tony crouches and doesn’t resist as Tony peels back his fingers and collar to see a bloody scratch on Peter’s shoulder. The same wound (albeit, not as deep) mirrored on his body where it was on Natasha's just a moment before.

Vaguely Tony registers the arrival of Bruce and the conversation of Clint explaining what happened with the intruder, the injury that isn’t anymore because _Mermaid did something and it went away_ , Bruce deciding that Natasha needs to be checked out for loss of blood anyways and _Tony, can you get Peter out of here? Security’s coming to get this guy out of our way and he shouldn’t be here when they do_.

“I heal fast,” Peter whispers to Tony. “These turn to scars fast.”

_Scars criss-crossing the kid’s body._

“Yeah, I got him,” Tony tells Bruce.

... 

...

...

“He didn’t appear on the cameras at all?” Obadiah says disbelievingly. This is the opposite of the first thing he wanted to wake up to. Finding out the building where your company runs its most important business has been easily broken into by a lunatic with unknown motives is the last thing anyone wants, probably, but least of all Obadiah Stane.

There are things he doesn’t want unknown hands shuffling through in the inner workings of that tower. Things only those who have been paid off into silence can know, otherwise the tenuous front of connection he keeps up with the ungrateful brat that is Tony Stark would easily snap.

“No, sir,” one useless security man reports. Useless, because look what happened on his watch.

Another guard refers him to the tapes, playing them back as he speaks: “You can see here the window breaking at the estimated time of entry, based on what the Avengers reported, but there is no direct evidence of a person coming in at all.”

“Aside from the fact that an unauthorized person _did_ come in,” Stane growls.

The men keep their gazes carefully averted.

Groaning, Obadiah reaches by habit for a cigar in his coat pocket but pauses, his doctor’s warnings chastising him in memory. He straightens his lapels instead and strides from the room like a thunder cloud off to storm someplace else.

He’ll have to visit the intruder at the Manhattan police station, obviously. He firmly subscribes to the belief that if you want a job done right, you do it yourself.

The man - beast of a man, really - looks remarkably calm for someone sitting handcuffed in a concrete holding cell. They tell him he’s got five minutes so he wastes no time.

“Why were you in my tower?”

The man’s coal gaze, appraising Obadiah from the moment he walked in, does not change at first. After a beat his lip curls in an animalistic way.

“I was thinking the ‘tower’ belonged to the Avengers, no?" he says in a gruff Russian accent.

“It is foremost a corporation,” the business man informs him coolly. “I am one of the original founders of that corporation and therefore, the use of a personal pronoun is wholly my right. Answer the question: Why were you there, and for that matter, how did you get in at all?”

The sneer on the wild man’s face twists into what almost looks like a smile; his eyes seem to see something of worth in the man before him because he reveals, “I am a hunter. Something valuable, a creature, it is hidden away in that place- but not from me. I will resume my pursuit shortly, as soon as my love retrieves me from this meager prison; her power is greater than your modern technology. You have seen how her charm tricked your little cameras.”

Obadiah’s first assessment is that the man is a drug addict with some major delusions, but key words (manly ‘valuable’ and ‘power’) stick out to him, give him pause. He handles himself with signature poise as he takes a seat across the table.

“Kraven, was it?” he says, not really caring for an answer before he goes on. “Kraven, it sounds like you’re a man with some traits I generally admire, persistence being one. Forgive me if I come across a little _uncultured_ by my _technology_ , but could you help me understand what you meant there by _creature_?”

Kraven does. 

 

It’s a short conversation, but Obadiah’s made life-altering (other people’s lives, mostly) business deals in shorter.

...

...

...

 

**Author's Note:**

> the 5-year-old within is yelling in delight
> 
> my tumblr: @the-reverse-mermaid


End file.
